Large networked supply
Information for a drinking water supply that normally serves more than 500 people through a network of pipes.
Key things you need to know as a provider of a large networked drinking water supply can be found on this page.
Register with us
If you're a new supplier, or an existing supplier who was registered under the previous regulator but has not yet registered with us, you'll need to register your supply with us on our Hinekōrako supply portal. The portal enables you to share important information with us about your supply.
Head to our registration page for more information and to access Hinekōrako.
Is some of your supply for agricultural use and some for domestic use?
If at least 50% of your water is used for agricultural or horticultural purposes (so less than 50% is used for domestic purposes) your supply can be categorised as mixed-use rural. That means you may be able to use an Acceptable Solution to show compliance with aspects of the Water Services Act 2021 rather than preparing a drinking water safety plan and following the Drinking Water Quality Assurance Rules shown below. Head to the mixed-use rural page to find out more.
Drinking water safety plan (DWSP)
Preparing a drinking water safety plan is a risk management process that aims to ensure a safe, reliable and resilient supply of drinking water to your consumers. If you are establishing a new supply or registering an existing supply, you will need to provide a DWSP unless you adopt an Acceptable Solution (see above).
What should be in a DWSP?
Your DWSP records the hazards and risks to your drinking water supply and how you will manage them to ensure that drinking water is safe. Your plan must:
- be proportionate to the scale and complexity of, and the risks that relate to, your drinking water supply
- identify any hazards that relate to your drinking water supply
- assess any risks associated with those hazards
- identify how those risks will be managed, controlled, or eliminated to ensure that the water you supply is safe and complies with the legislative requirements of the Water Services Act 2021
- identify how the DWSP will be reviewed on an ongoing basis, and how its implementation will be amended, if necessary, to ensure that the drinking water you supply is safe and complies with legislative requirements
- identify how your drinking water supply will be monitored to ensure that drinking water is safe and complies with legislative requirements
- include procedures to verify that your DWSP is working effectively
- include a multi-barrier approach to drinking water safety that will be implemented as part of the DWSP
- include a source water risk management plan if required
- if your supply includes reticulation, require, and provide for the use of, residual disinfection in the supply unless an exemption is obtained
- identify how you will meet your duty as a supplier to ensure that a sufficient quantity of drinking water is provided
- identify how you will respond to events and emergencies in relation to your supply
- comply with the relevant requirements of the Drinking Water Quality Assurance Rules (the Rules).
Source water risk management plan
A source water risk management plan is part of your DWSP, unless your supply doesn’t have a source (for example, you receive water from another supplier). It sets out how hazards and risks in your source water will be managed. One step in the development of your plan will be engaging with local authorities to understand the risks to your water source.
A source water risk management plan must:
- identify any hazards that relate to the source water, including emerging or potential hazards
- assess any risks that are associated with those hazards
- identify how those risks will be managed, controlled, monitored or eliminated as part of a DWSP
- include a description of the land surrounding the source water or the groundwater catchment
- have regard to any values identified by local authorities under the National Policy Statement for Freshwater Management (made under the Resource Management Act 1991) that relate to a freshwater body that you use as a source of your drinking water supply.
Is your supply partly for agricultural use and partly for domestic use?
If your supply is used partly for agricultural purposes (e.g. for example, irrigation or stock water) and partly for domestic purposes (including drinking water), and no more than 50% of the supply is for domestic use, it could be categorised as a Mixed-use Rural supply.
Mixed-use Rural suppliers can comply with some requirements of the Act by using a readymade alternative option called an Acceptable Solution. If you choose to comply using the Mixed-use Rural Acceptable Solution, you will not need to prepare a drinking water safety plan or follow the rules below.
Submitting your DWSP
We have prepared this guide to uploading your DWSP to Hinekōrakooutbound.
Rule types, reporting, and compliance periods
Monitoring rules
Monitoring rules set out requirements to monitor the quality of source water and treated water. They cover determinands and parameters that need to be either continuously monitored or regularly sampled. Monitoring rules have compliance periods of 1 day, 1 month, 3 months, or 1 year, which typically depends on the frequency of monitoring required in the rule.
1-day compliance periods
A monitoring rule which requires a determinand or parameter to be continuously monitored or monitored daily, irrespective of the period of the day that the supply is operating, has a compliance period of 1 day, i.e. 24 hours (midnight to midnight).
1-month compliance periods
A monitoring rule which requires a determinand or parameter to be monitored on a monthly or weekly basis, e.g. 2 per week, 8 per month, etc., has a compliance period of 1 month.
3-month compliance periods
A monitoring rule which requires a determinand or parameter to be monitored at least every 3 months has a compliance period of 3 months.
1-year compliance periods
All other monitoring rules have a compliance period of 1 year.
Note: Where monitoring occurs at least every 3 years or at least every 5 years, the rule must be reported annually. It will be compliant if the monitoring was not due that year or if the monitoring was due and was undertaken.
Assurance rules
Assurance rules cover activities that water suppliers need to undertake, for example the preparation of a backflow prevention programme or a distribution zone sampling plan. Assurance rules are used to indicate whether water suppliers undertake activities that contribute to the provision of safe drinking water.
Assurance rules have a compliance period of 1 year.
Non-reporting rules
Some rules are designated as non-reporting rules and water suppliers are not required to report on their performance against those rules, though they are still expected to comply with the requirements of the rules. Non-reporting rules have no compliance period as they do not have to be reported on.
The rules that apply to this type of supply are listed below. You can download the complete Drinking Water Quality Assurance Rules here.
General Rules
The following Level 3 General Drinking Water Quality Assurance Rules apply.
Rule G3 – reporting requirements (assurance rule)
Drinking water suppliers demonstrating compliance against level 3 Rules must report to the Water Services Authority – Taumata Arowai the water quality monitoring information set out in tables 5, 6 and 7.
Compliance period: As set out in tables 5, 6 and 7.
Note: Reports must be provided to the Water Services Authority – Taumata Arowai within 10 working days of the end of each month.
|
Rule* |
Parameter |
Compliance period |
Reporting period** |
|
If chlorine is the primary disinfectant |
|||
|
T3.2 |
Chlorine C.t |
1 day |
1 month |
|
If chlorine dioxide is the primary disinfectant |
|||
|
T3.8 |
Chlorine dioxide C.t |
1 day |
1 month |
|
If ozone is the primary disinfectant |
|||
|
T3.13 |
Ozone residual |
1 day |
1 month |
|
If UV is the primary disinfectant |
|||
|
T3.17 |
UV dose |
1 day |
1 month |
|
Rule*** |
Parameter |
Compliance period |
Reporting period** |
|
For Coagulation, Flocculation and Sedimentation without Filtration |
|||
|
T3.24 |
Turbidity |
1 day |
1 month |
|
For Coagulation, Flocculation and Sedimentation with Filtration, Second Stage Filtration, Slow Sand Filtration, Membrane Filtration or Cartridge Filtration |
|||
|
Depending on process used, either: |
Turbidity |
1 day |
1 month |
|
For ozone |
|||
|
T3.81 |
Ozone C.t |
1 day |
1 month |
|
If UV is the primary disinfectant |
|||
|
T3.86 |
UV dose |
1 day |
1 month |
|
Rule number |
Parameter |
Compliance period |
Reporting period** |
|
D3.19 |
FAC |
1 month |
1 month |
|
D3.29 |
E. coli, total coliforms |
1 month |
1 month |
* Reporting is only required against one of the rules in this column depending on whether chlorine, ozone or UV is used as the primary disinfectant.
** Report must be provided to Taumata Arowai within 10 working days of the end of each month.
*** Reporting is only required against one pair (in brackets) of the rules in this column depending on the process that is used to demonstrate an effective protozoa barrier.
Rule G4 – reporting requirements (assurance rule)
Drinking water suppliers reporting against level 3 monitoring rules that are not included in tables 5, 6, and 7 must report annually within 40 working days of the end of each calendar year.
Compliance period: As set out in the relevant rules
Rule G5 – reporting requirements (assurance rule)
Drinking water suppliers demonstrating compliance with level 3 rules, must report on their performance against all assurance rules annually within 40 days of the end of each calendar year.
Compliance period: 1 year
Clarification: The deadline for reporting may be interpreted to be "within 40 working days of the end of each calendar year." This aligns with the requirement of annual reporting against monitoring rules in rule G4.
Rule G6 – sample labelling (assurance rule)
All samples collected from drinking water supplies for monitoring that are analysed by laboratories, must be labelled with the unique source, treatment plant, distribution zone, or Water Carrier Service identifier allocated by Taumata Arowai, to show where the sample was collected from and the time and date that the sample was collected.
Compliance period: 1 year
Rule G7 – sample delivery (assurance rule)
Drinking water suppliers must take reasonably practicable steps to ensure that samples for E. coli, total coliforms, or other microbiological contaminants are delivered to a laboratory within 24 hours of the sample being collected, and at a water temperature that is no higher than the water temperature at the time of sampling but above zero degrees Celsius.
Compliance period: 1 year
Rule G8 – sample analysis (assurance rule)
All water samples that require laboratory analysis and are used to demonstrate compliance with these Rules must be:
a. analysed by a laboratory accredited by IANZ for the type of analysis being undertaken; and
b. collected according to any instructions and specifications provided by the laboratory.
Compliance period: 1 year
Rule G9 – sampling equipment (assurance rule)
Equipment used for the analysis of single samples (grab samples) by drinking water suppliers, to demonstrate compliance with any rule, must be calibrated/verified in accordance with the instrument manufacturer’s specified procedures and frequency.
Compliance period: 1 year
Rule G10 – worker experience (assurance rule)
All work (planned or unplanned) on a water supply must be completed by suitably trained or experienced personnel.
Compliance period: 1 year
Rule G11 – worker hygiene (assurance rule)
Drinking water suppliers must prepare a hygiene code of practice for people working on a water supply which must include:
a. maintenance of personal hygiene at all times; and
b. prohibition of people working on a water system who are experiencing any gastrointestinal illness; and
c. protection of the work site, materials, and tools from contamination; and
d. how all reasonable steps will be taken to minimise the entry of contamination into the water supply during any activity.
Compliance period: 1 year
Rule G12 – continuous monitoring equipment (assurance rule)
Continuous online monitoring equipment used to demonstrate compliance with any rule must:
a. be calibrated in accordance with the instrument manufacturer’s specified procedures and frequency; and
b. have calibration verified in accordance with the instrument manufacturer’s specified procedures.
Compliance period: 1 year
Rule G13 – continuous monitoring equipment (assurance rule)
For continuous monitoring equipment that is used to demonstrate compliance against treatment Rules (T1, T2, T3), the separation between data records must be no more than 1 minute.
Note: Separation between data records of up to five minutes is allowed for FAC analysers and fluoride analysers where the minimum cycle time specified by the analyser manufacturer exceeds 1 minute.
Compliance period: 1 year
Rule G14 – continuous monitoring data (assurance rule)
Generation of continuous monitoring data that is used to demonstrate compliance against T3 treatment Rules or D3 Distribution Rules, must not be interrupted for a period of more than 15 consecutive minutes, or for a total of more than 72 minutes in any one-day compliance period, for compliance to be achieved.
Compliance period: 1 year
Clarification: For D3 Distribution System Rules, like D3.19, which may require the generation of continuous monitoring data, that data must not be interrupted for more than 3 consecutive hours in any 1 day compliance period, for compliance to be achieved.
Rule G15 – continuous monitoring equipment (assurance rule)
For continuous monitoring equipment that is used to assess source water or to demonstrate compliance against distribution zone Rules, the separation between data records must be no more than 30 minutes.
Compliance period: 1 year
Clarification: For D3 Distribution System Rules, like D3.19, which may require the generation of continuous monitoring data, that data must not be interrupted for more than 3 consecutive hours in any 1 day compliance period, for compliance to be achieved.
Rule G16 – continuous monitoring equipment (assurance rule)
Continuous monitoring equipment used to monitor FAC in distribution zones must be appropriately pH and temperature compensated.
Compliance period: 1 year
Rule G17 – continuous monitoring equipment (assurance rule)
Where continuous monitoring equipment that is used to demonstrate compliance (excludes source water monitoring) fails, or is not otherwise able to provide data, grab samples can be taken to substitute for continuous data if analyses of the parameters is undertaken for at least every 30-minute period that the continuous monitoring equipment is not operating.
Compliance period: Dependent on the parameter and circumstances
Source Water Rules
The following S3 Source Water Rules and requirements apply.
S3 source water protozoa log credit treatment requirements
Drinking water suppliers must determine the level of protozoa treatment required for a drinking water supply based on the requirements set out in the source classifications below. Treatment systems must provide a protozoa barrier equal to or exceeding the source water log credit treatment requirements for the applicable source water class.
Class 1 – protozoa barrier not required
Criteria
Groundwater sources (bore water) that draw water from a depth of more than 30 metres below ground level (with depth measured from ground level to the top of the upper most screen) and via a sanitary bore head in which E. coli and total coliforms have not been detected over a period of three years* (monthly samples with a maximum of 45 days between samples).
If a groundwater source has demonstrated Class 1 status but any result for E. coli or total coliforms is positive, the groundwater source must assume Interim Class 1 status.
* Samples can be from individual bores or water combined from up to six bores if the water is from the same aquifer and has similar characteristics.
Interim Class 1
If a drinking water supplier intends to demonstrate Class 1 status for a groundwater source (bore water) but does not have the required E. coli or total coliforms data, they may demonstrate Interim Class 1 status by monitoring E. coli and total coliforms in bore water** daily for 36 days, and then weekly until 52 weeks of data has accrued with no E. coli or total coliforms detected. If any sample for E. coli or total coliforms is positive, the process must begin again until 52 weeks of data has accrued with negative results.
If Class 1 category cannot be established within 24 months of beginning sampling, the water source must be classified as Class 2.
** Samples can be from individual bores or water combined from up to six bores if the water is from the same aquifer and has similar characteristics.
Class 2 – Protozoa barrier – 3 log
Criteria
Groundwater sources that draw water from a depth of between 30 metres and 10 metres below ground level (with depth measured from ground level to the top of the upper most screen).
Clarification: Groundwater sources that:
- draw water from a depth of greater than 10 metres below ground level (with depth measured from ground level to the top of the uppermost screen); and
- are not classified as Class 1 or Interim Class 1 source water.
Class 3 – Protozoa Barrier – 4 log
Criteria
Groundwater sources that draw water from a depth of less than 10 metres below ground level (with depth measured from ground level to the top of the upper most screen), groundwater sources that draw water from a depth of 10 or more metres below ground level without a sanitary bore head, spring water sources and surface water sources.
Clarification: Groundwater sources that draw water from a depth of 10 metres or less below ground level (with depth measured from ground level to the top of the uppermost screen), spring water sources and surface water sources.
Class 4 – Protozoa Barrier – 3 log
Criteria
Drinking water supplies that require a minimum protozoa treatment barrier of 4-log may reduce the level of protozoa treatment to a minimum of 3-log if the source water risk management plan for the supply provides evidence that the source water has a low risk of protozoa contamination.
S3 sanitary bore head requirements
A bore head is considered a sanitary bore head if it meets all of the following criteria:
- The bore head is installed above ground.
- The bore is installed in an area of ground that is not below the surrounding ground level such that ponding could occur around the bore head during rainfall.
- The annulus of the casing is sealed taking account of the formation that the bore has been installed in, to prevent the ingress of surface water via the outside of the casing and the bore is grouted below ground to an appropriate depth.
- A concrete apron is installed around the bore head, extending a minimum of one metre in all directions from the casing and sloping away from the casing so that any water on the ground surface is carried away from the bore.
- All apertures into the bore (for cables etc) are sealed and watertight to prevent access from water and vermin-proofed to prevent access by small animals etc.
- All air vents and any other apertures that are not watertight must be screened to prevent access by small animals, face downwards, and be elevated at least 0.5 metres above the surrounding ground level.
- Reasonable security measures are in place to protect the bore head from unauthorised access or interference.
- If the bore head is in an area where farm animals are present, it must be fenced to exclude those animals from an area extending at least five metres in all directions from the bore head.
- A mechanism prevents backflow at the bore head.
- The bore head is inspected monthly for damage or defects and records kept of all inspections for at least five years.
Rule S3.1 - class determination (assurance rule)
Water suppliers must determine the class of source water for each of the source waters that are used, based on the Source Water Protozoa Log Credit Treatment Requirements.
Compliance period: 1 year
Rule S3.2 - bore requirements (assurance rule)
A drinking water supplier demonstrating Class 1 or Interim Class 1 groundwater must document whether or not the bore meets the requirements of a sanitary bore head.
Compliance period: 1 year
Rule S3.3 - determinand monitoring (monitoring rule)
All source waters must be monitored for the determinands and at the frequencies set out in Table 16 and Table 18 below.
The reporting period is 1 year.
|
Determinand group |
Determinands monitored at each abstraction point* ** |
Sampling frequency |
|
Bacterial |
E. coli, total coliforms |
2 per month |
|
Physico-chemical |
Iron, manganese, colour, nitrate |
Monthly |
|
Alkalinity, antimony, arsenic, barium, cadmium, calcium, chloride, chromium, copper, lead, magnesium, mercury, nickel, sodium, sulphate. |
Annually*** |
* Samples may be collected either at the source abstraction point or at the treatment plant before any form of treatment, if water is from a single source. If multiple sources are used, samples must be collected from each source at points before any mixing of source water occurs.
** Where multiple bores access the same aquifer, one bore can be sampled to provide results that are representative of a number of bores if the water supplier can demonstrate that the bore that is sampled is representative of the bores that are not sampled. The representative nature of the sampled bore must be reestablished every five years or after significant seismic activity.
*** Must be sampled monthly if the determinand exceeds 50% of its MAV. Sampling may return to annually after 12 consecutive samples are less than 50% of the MAV.
|
Parameters monitored in raw water from each source or combined sources* |
Sampling frequency |
|
|
Class 1 and Interim Class 1 |
||
|
Physico-chemical |
Conductivity, pH, turbidity |
Monthly for 12 months Every 6 months if there is no significant variation in the initial 12 months of samples** |
|
Classes 2, 3 and 4 |
||
|
Physico-chemical |
Conductivity, pH, turbidity |
Continuous*** |
* If water is abstracted from more than one source and combined at the treatment plant, only the combined water needs to be analysed and this can be done at the treatment plant before any form of treatment.
** If a six-monthly sample varies significantly from previous samples, sampling should return to monthly for 12 months
*** Where continuous monitoring analysers fail or require maintenance, daily grab samples can be taken until the continuous monitoring equipment can be brought back into service.
Rule S3.4 - radiological determinand monitoring (monitoring rule)
All groundwaters must be monitored for the radiological determinands set out in Table 17 below.
The reporting period is 1 year.
|
Determinand group |
Determinands monitored at each source* ** |
Sampling frequency |
|
Radiological |
Gross alpha activity |
Every 10 years |
|
Chemical |
Potassium*** |
Every 10 years |
* Samples may be collected either at the source abstraction point or at the treatment plant before any form of treatment, if water is from a single source. If multiple sources are used, samples must be collected from each source at points before any mixing of source water occurs.
** Where multiple bores access the same aquifer, one bore can be sampled to provide results that are representative of a number of bores if the water supplier can demonstrate that the bore that is sampled is representative of the bores that are not sampled.
*** When samples are analysed for alpha and beta emitting particles a sample for potassium must also be analysed so that the potassium 40 contribution to beta emitting particles can be determined.
Rule S3.5 - monitoring after severe weather (monitoring rule)
Additional monitoring of Class 2, Class 3 and Class 4 source waters must be undertaken either during or immediately after a severe or extreme weather event or other events which could adversely affect source water quality.
Note:
- Samples of raw water may be collected at the treatment plant for this purpose.
- Samples should not be collected if there are health and safety risks to people collecting samples that are not appropriately eliminated or minimised.
Rule S3.6 - monitoring for additional determinands (monitoring rule)
Monitoring of source water must be undertaken for any determinand additional to those set out in Tables 16 and 18 (see rule S3.3 above) if the determinand has been identified in the drinking water supply Source Water Risk Management Plan as presenting a potential risk to the drinking water supply.
Compliance period: As determined by the Source Water Risk Management Plan
Rule S3.7 - risk categorisation (assurance rule)
Water sources must be categorised as either low-risk, medium-risk or high-risk for the presence of cyanobacteria.
Compliance period: 1 year
Rule S3.8 - cyanobacteria/cyanotoxin response plan
When a water supply is categorised as medium or high-risk under rule S3.7, a cyanobacteria / cyanotoxin response plan must be prepared which includes vigilance levels for assessing the presence of cyanobacteria and alert levels related to the presence of cyanotoxins, monitoring for cyanobacteria/cyanotoxins and the action that will be taken to protect consumers.
Compliance period: 1 year
Rule S3.9 - cyanobacteria/cyanotoxin monitoring (assurance rule)
If a water supplier becomes aware of the presence of cyanobacteria in source water, monitoring to determine the level of cyanobacteria and/or cyanotoxin levels must be considered in accordance with the cyanobacteria/cyanotoxin response plan.
Compliance period: 1 year
Treatment Rules
The following T3 Treatment Rules and requirements apply.
Clarification: Additional clarification for requirements to meet a parameter for a percentage of a day when a treatment plant or process does not operate for all of a day:
A treatment plant or process “is operating” when it is producing drinking water to be distributed to consumers.
Example: Rule T3.5 should be interpreted as:
The turbidity of water leaving the treatment plant must be less than 1 NTU for at least 95% of the time the treatment plant is producing drinking water to be distributed to consumers.
T3 Bacterial Rules
One or more of the following options must be used to demonstrate bacterial compliance.
- Disinfection with chorine
- Disinfection with chlorine dioxide
- Disinfection with ozone
- Disinfection with UV light
T3 bacterial rules for water disinfected with chlorine
Rule T3.1 (monitoring rule)
All water passing through the treatment plant must be treated with chlorine and must be monitored in accordance with Table 19.
Compliance period: 1 day
Rule T3.2 (monitoring rule)
Treated water must achieve a chlorine C.t value of at least 15 min.mg/L for at least 95 % of each day.
Compliance period: 1 day
Rule T3.3 (monitoring rule)
Treated water must have a FACE of no less than 0.2 mg/L.
Compliance period: 1 day
Rule T3.4 (monitoring rule)
T10 contact time of at least 5 minutes must be demonstrated.
Compliance period: 1 day
Rule T3.5 (monitoring rule)
Turbidity of water leaving the treatment plant must be less than 1.0 NTU for at least 95% of each day.
Note: Where lime is used for post-treatment pH adjustment, analysis may be undertaken before the lime is dosed.
Compliance period: 1 day
Rule T3.6 (monitoring rule)
Turbidity must not exceed 2.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
|
Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: FAC Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
Parameters: pH Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
|
Parameters: Turbidity Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
|
Parameters: Flow Where it needs to be monitored: Water leaving the contact tank unless there is a high-level outlet weir in which case water entering the contact tank is acceptable. A calculated outlet flow based on inlet flow and contact level change is also an acceptable approach. |
|
|
Water level in the contact tank (if used) |
|
|
Values that need to be continuously monitored: |
FACE |
|
T10 Contact Time |
|
|
C.t |
T3 bacterial rules for water disinfected with chlorine dioxide
Rule T3.7 (monitoring rule)
All water passing through the treatment plant must be treated with chlorine and must be monitored in accordance with Table 20.
Compliance period: 1 day
Rule T3.8 (monitoring rule)
Treated water must achieve a chlorine C.t value of at least 15 min.mg/L for at least 95 % of each day.
Compliance period: 1 day
Rule T3.9 (monitoring rule)
T10 contact time of at least 5 minutes must be demonstrated.
Compliance period: 1 day
Rule T3.10 (monitoring rule)
Turbidity of water leaving the treatment plant must be less than 1.0 NTU for at least 95% of each day.
Note: Where lime is used for pH adjustment, samples may be taken before the lime is dosed.
Compliance period: 1 day
Rule T3.11 (monitoring rule)
Turbidity must not exceed 2.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
|
Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Chlorine dioxide Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
Parameters: FAC if used in combination with chlorine dioxide Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
|
Parameters: pH Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
|
Parameters: Turbidity Where it needs to be monitored: Water at a point after the prescribed disinfection contact time has elapsed. |
|
|
Parameters: Flow Where it needs to be monitored: Water leaving the contact tank unless there is a high-level outlet weir in which case water entering the contact tank is acceptable. A calculated outlet flow based on inlet flow and contact level change is also an acceptable approach. |
|
|
Water level in the contact tank (if used) |
|
|
Values that need to be continuously monitored: |
FACE if chlorine is used in combination with chlorine dioxide |
|
Total disinfectant |
|
|
T10 Contact Time |
|
|
C.t |
T3 bacterial rules for water disinfected with ozone
Rule T3.12 (monitoring rule)
All water passing through the treatment plant must pass through the ozone contactor and must be monitored in accordance with Table 21.
Compliance period: 1 day
Rule T3.13 (monitoring rule)
C.t of at least 1.2 mg.min/L for more than 95% of each day must be achieved.
Compliance period: 1 day
Rule T3.14 (monitoring rule)
Turbidity must not exceed 5.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
|
Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Ozone Residual Where it needs to be monitored: Water leaving the contact tank. Additional monitoring sites may be used in addition to the contact tank exit point if the water supplier can demonstrate that they improve the accuracy of the monitoring information. |
|
Parameters: Turbidity Where it needs to be monitored: Water at a point immediately before or after the contact tank. |
|
|
Parameters: Flow Where it needs to be monitored: Water leaving the contact tank unless there is a high-level outlet weir in which case water entering the contact tank is acceptable. A calculated outlet flow based on inlet flow and contact level change is also an acceptable approach. |
|
|
Water level in the contact tank (if used) |
|
|
Values that need to be continuously monitored: |
T10 Contact Time |
|
C.t (Ozone x T10 Contact Time). |
T3 bacterial rules for water disinfected with ultraviolet light
Rule T3.15 (monitoring rule)
All water passing through the treatment plant must pass through the UV reactor(s) and be within the reactor’s certified flow range and must be monitored in accordance with Table 22.
Clarifications:
The requirements of section 4.10.1.4 Table 22 are the same as the requirements of 4.10.2.13 Table 32 (footnote 56) (page 62): The requirement to monitor UVT does not apply to UV disinfection systems that automatically adjust the UV dose as the UVT of the water flowing through the reactor varies. The UV disinfection system may still require monitoring of UVT to meet the manufacturers’ validation criteria and requirements.
The requirement to undertake monthly UV sensor checks has a 1 month compliance period. This should be reported under Reporting Rule IDs T3.15-sens or T3.91-sens. There is no change to the reporting period, which is 1 year.
Compliance period: 1 day
Rule T3.16 (monitoring rule)
A reduction equivalent dose (RED) of not less than 40 mJ/cm2 (or equivalent) must be achieved for not less than 95 % of each day.
Clarification: If any reactor fails more than 5% of the time it operates during the day, then the whole process fails for the day. Alternatively, the compliant percentage of total production volume through all UV reactors may be used to calculate whether the whole process passes/fails the 95% criteria for the day.
Compliance period: 1 day
Rule T3.17 (monitoring rule)
The RED UV dose must be not less than 40 mJ/cm2 for any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.18 (monitoring rule)
Turbidity must not exceed 5.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.19 (assurance rule)
For UV units certified to Ultraviolet Disinfection Guidance Manual (USEPA 2006b) monitored UVI, UVT and flow must be used to calculate dose.
Compliance period: 1 year
Rule T3.20 (assurance rule)
For UV units certified to DVGW Technical Standard W294 (DVGW 2006) or ÖNORM M 5873-1: 2020 01 01 (Or UV reactors certified to ÖNORM M5873 (Osterreichisches Normungsinstitut 2001)) monitored flow must be used for UVI control or the reactor run at full power. UVI and UVT must be more than the validated value for the respective flow.
Clarification:
The transition of DVGW Technical Standard W294 to DIN 19294.
A new DIN 19294-1:2020-08 Standard has been released to replace DVGW Technical Standard W294-2. The DIN 19294-1:2020-08 and ÖNORM M 5873-1:2020-01-01 are identical in content, therefore where ÖNORM M5873-1:2020-01-01 is referenced the DIN 19294-1:2020-08 will also be accepted as a suitable UV validation/certification standard.
All rules and requirements applicable to ÖNORM M5873-1:2020-01-01 apply to DIN 19294-1:2020-08.
Compliance period: 1 year
Rule T3.21 (assurance rule)
For UV units certified to NSF/ANSI 55 Class A (NSF, ANSI n.d.); (for populations of up to 5000) – 3-log a fault must be generated when any parameter exceeds the certified value.
Compliance period: 1 year
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: UVT Where it needs to be monitored: Water entering or leaving the UV reactor(s). Note: Does not apply to UV units certified to NSF/ANSI 55 (NSF, ANSI nd) for Class A systems (for populations of up to 5000) – 3-log. |
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Parameters: Turbidity Where it needs to be monitored: Water entering or leaving the UV reactor(s). Can include upstream filter monitoring if there is no other process between the filters and the UV reactors. |
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Parameters: UVI or dose Where it needs to be monitored: The same point in the reactor as that used for certification/validation. |
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Parameters: Flow Where it needs to be monitored: At a point representative of water entering or leaving the reactor(s). |
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UVI sensor checking and standardisation: |
Duty UVI sensors must be checked at least monthly against the reference sensor. If the difference between the two readings exceeds the manufacturer’s specified limits, then the Duty UVI sensor must be replaced. The reference UVI sensor must be standardised at least annually in accordance with Ultraviolet Disinfection Guidance Manual (USEPA 2006b) or other traceable procedure. Alternatively, after 12 months the drinking water supplier can use the reference sensor as a duty sensor and purchase a new standardised sensor for use as a reference sensor. |
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UV certification/validation: |
The equipment must be certified and operated to meet the RED dose of 40 mJ/cm2 (or equivalent) using at least one of the: NSF/ANSI 55 (NSF, ANSI nd) for Class A systems (for populations of up to 5000) – 3-log. |
T3 Protozoal Rules
Rule T3.22 (assurance rule)
Drinking water supplies must have a protozoa barrier that provides treatment equal to or exceeding the log level of the water class identified by the Source Water Protozoa Log Credit Treatment Requirements.
Compliance period: 1 year
Treatment processes and log credit allocations
There are 9 processes that can be used for protozoal treatment. Each process has log credits that can be achieved if that process is chosen.
The cumulative log credits of a process that includes filtration or sedimentation and a disinfection process can be calculated by adding the log credits of the qualifying processes that you use. If two filtration processes are used, the second filtration process is considered to be second-stage filtration and can add only 0.5-Log to the cumulative log credits.
The log process(es) you can use are:
- Coagulation, flocculation and sedimentation process without filtration [0.5-Log]
- Coagulation, flocculation and direct filtration [2.5-3.5-Log]
- Coagulation, flocculation, sedimentation and filtration [3-4-Log]
- Second stage filtration [0.5-Log]
- Slow sand filtration [2.5-Log]
- Membrane filtration [up to 4.0-Log]
- Cartridge filtration [2.0-Log]
- Ozone [0.25 to 3.0-Log]
- Ultraviolet light [up to 4-Log]
The rules applying to each are shown below.
T3 requirements for coagulation, flocculation and sedimentation without filtration
Rule T3.23 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation and sedimentation process.
Compliance period: 1 year
Rule T3.24 (monitoring rule)
The sedimentation process must achieve at least a 70% reduction in raw water turbidity each day, based on the arithmetic mean of the turbidity of the raw water and the water leaving the sedimentation process.
Compliance period: 1 day
T3.25 (monitoring rule)
All of the monitoring requirements in Table 23 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameter: Turbidity. Where it needs to be monitored: On the inlet and outlet of sedimentation process. |
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Process limitations: |
Sedimentation includes dissolved air flotation. |
Clarification: The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
T3 protozoal rules for coagulation, flocculation and direct filtration [2.5-Log]
Rule T3.26 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation, and filtration process.
Compliance period: 1 year
Rule T3.27 (monitoring rule)
Turbidity must not exceed 0.3 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.28 (monitoring rule)
Turbidity must not exceed 0.5 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.29 (monitoring rule)
All of the requirements in Table 24 must be met.
Compliance period: 1 day
T3 protozoal rules for coagulation, flocculation and direct filtration [3.0-Log]
Rule T3.30 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation, and filtration process.
Compliance period: 1 year
Rule T3.31 (monitoring rule)
Turbidity must not exceed 0.15 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.32 (monitoring rule)
Turbidity must not exceed 0.5 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.33 (monitoring rule)
All of the requirements in Table 24 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameter: Turbidity Where it needs to be monitored: On the outlet of each filter. Monitored when the filter is in service to supply, on any recycle streams to the plant inlet (if present). |
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Parameter: Service State. Where it needs to be monitored: Each filter. |
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Process limitations: |
Filtration is of a rapid media design (pressure or gravity equivalent). Water treatment plants that recycle waste streams (excluding water from rapid media filters being diverted during restart after backwash, often called ‘filter to waste’) must return the recycle stream so that it undergoes the full treatment process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If instantaneous total return rate flows of greater than 10% of the plant inflow are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant inlet. |
T3 protozoal rules for coagulation, flocculation and direct filtration [3.5-Log]
Rule T3.34 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation and filtration process.
Compliance period: 1 year
Rule T3.35 (monitoring rule)
Turbidity must not exceed 0.1 NTU for more than 5% of each day
Compliance period: 1 day
Rule T3.36 (monitoring rule)
Turbidity must not exceed 0.3 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.37 (monitoring rule)
All of the monitoring requirements in Table 24 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameter: Turbidity Where it needs to be monitored: On the outlet of each filter. Monitored when the filter is in service to supply, on any recycle streams to the plant inlet (if present). |
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Parameter: Service State. Where it needs to be monitored: Each filter. |
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Process limitations: |
Filtration is of a rapid media design (pressure or gravity equivalent). Water treatment plants that recycle waste streams (excluding water from rapid media filters being diverted during restart after backwash, often called ‘filter to waste’) must return the recycle stream so that it undergoes the full treatment process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If instantaneous total return rate flows of greater than 10% of the plant inflow are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant inlet. |
Clarifications:
The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
Additional clarification for treatment plants with recycle streams:
- Drinking water treatment plants that have recycled waste streams must operate under T3 Treatment Rules due to the increased risk profile of recycled waste streams. To avoid doubt, recycling of waste streams cannot be done if a supplier elects to comply with T1 and T2 Treatment Rules for a drinking water treatment plant.
- Recycle waste streams (except water filtered through rapid media filters being diverted to waste) require some form of liquid/solids separation before the waste stream is returned to the plant upstream of the relevant treatment processes.
- A sedimentation basin/tank will not meet the requirement for “some form of liquids/solids separation” above for treatment plants where total recycle return rates exceed 10%.
The requirements to monitor the recycle stream may be reported under the respective Reporting Rule IDs with a suffix of "-recy". These are continuous monitoring requirements, which have a 1 day compliance period.
T3 protozoal rules for coagulation, sedimentation and filtration [3-Log]
Rule T3.38 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation, sedimentation, and filtration process.
Compliance period: 1 year
Rule T3.39 (monitoring rule)
Turbidity must not exceed 0.3 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.40 (monitoring rule)
Turbidity must not exceed 0.5 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.41 (monitoring rule)
All of the monitoring in Table 25 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Turbidity. Where it needs to be monitored: On the outlet of each filter. Monitored when the filter is in service to supply, on any recycle streams to the plant inlet (if present). |
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Parameter: Service State. Where it needs to be monitored: Each filter. |
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Process limitations: |
Sedimentation includes dissolved air flotation. Filtration is of a rapid media design (pressure or gravity equivalent). Water treatment plants that recycle waste streams (excluding water from rapid media filters being diverted during restart after backwash, often called ‘filter to waste’) must return the recycle stream so that it undergoes the full treatment process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If flows of greater than 10% are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant inlet. |
Clarifications:
The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
Additional clarification for treatment plants with recycle streams:
- Drinking water treatment plants that have recycled waste streams must operate under T3 Treatment Rules due to the increased risk profile of recycled waste streams. To avoid doubt, recycling of waste streams cannot be done if a supplier elects to comply with T1 and T2 Treatment Rules for a drinking water treatment plant.
- Recycle waste streams (except water filtered through rapid media filters being diverted to waste) require some form of liquid/solids separation before the waste stream is returned to the plant upstream of the relevant treatment processes.
- A sedimentation basin/tank will not meet the requirement for “some form of liquids/solids separation” above for treatment plants where total recycle return rates exceed 10%.
The requirements to monitor the recycle stream may be reported under the respective Reporting Rule IDs with a suffix of "-recy". These are continuous monitoring requirements, which have a 1 day compliance period.
T3 protozoal rules for coagulation, sedimentation and filtration [3.5-Log]
Rule T3.42 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation, sedimentation, and filtration process.
Compliance period: 1 year
Rule T3.43 (monitoring rule)
Turbidity must not exceed 0.15 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.44 (monitoring rule)
Turbidity must not exceed 0.5 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.45 (monitoring rule)
All of the monitoring in Table 25 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Turbidity. Where it needs to be monitored: On the outlet of each filter. Monitored when the filter is in service to supply, on any recycle streams to the plant inlet (if present). |
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Parameter: Service State. Where it needs to be monitored: Each filter. |
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Process limitations: |
Sedimentation includes dissolved air flotation. Filtration is of a rapid media design (pressure or gravity equivalent). Water treatment plants that recycle waste streams (excluding water from rapid media filters being diverted during restart after backwash, often called ‘filter to waste’) must return the recycle stream so that it undergoes the full treatment process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If flows of greater than 10% are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant inlet. |
Clarifications:
The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
Additional clarification for treatment plants with recycle streams:
- Drinking water treatment plants that have recycled waste streams must operate under T3 Treatment Rules due to the increased risk profile of recycled waste streams. To avoid doubt, recycling of waste streams cannot be done if a supplier elects to comply with T1 and T2 Treatment Rules for a drinking water treatment plant.
- Recycle waste streams (except water filtered through rapid media filters being diverted to waste) require some form of liquid/solids separation before the waste stream is returned to the plant upstream of the relevant treatment processes.
- A sedimentation basin/tank will not meet the requirement for “some form of liquids/solids separation” above for treatment plants where total recycle return rates exceed 10%.
The requirements to monitor the recycle stream may be reported under the respective Reporting Rule IDs with a suffix of "-recy". These are continuous monitoring requirements, which have a 1 day compliance period.
T3 protozoal rules for coagulation, sedimentation and filtration [4-Log]
Rule T3.46 (assurance rule)
All water passing through the treatment plant must pass through the coagulation, flocculation, sedimentation, and filtration process.
Compliance period: 1 year
Rule T3.47 (monitoring rule)
Turbidity must not exceed 0.1 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.48 (monitoring rule)
Turbidity must not exceed 0.3 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.49 (monitoring rule)
All of the monitoring in Table 25 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Turbidity. Where it needs to be monitored: On the outlet of each filter. Monitored when the filter is in service to supply, on any recycle streams to the plant inlet (if present). |
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Parameter: Service State. Where it needs to be monitored: Each filter. |
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Process limitations: |
Sedimentation includes dissolved air flotation. Filtration is of a rapid media design (pressure or gravity equivalent). Water treatment plants that recycle waste streams (excluding water from rapid media filters being diverted during restart after backwash, often called ‘filter to waste’) must return the recycle stream so that it undergoes the full treatment process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If flows of greater than 10% are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant inlet. |
Clarifications:
The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
Additional clarification for treatment plants with recycle streams:
- Drinking water treatment plants that have recycled waste streams must operate under T3 Treatment Rules due to the increased risk profile of recycled waste streams. To avoid doubt, recycling of waste streams cannot be done if a supplier elects to comply with T1 and T2 Treatment Rules for a drinking water treatment plant.
- Recycle waste streams (except water filtered through rapid media filters being diverted to waste) require some form of liquid/solids separation before the waste stream is returned to the plant upstream of the relevant treatment processes.
- A sedimentation basin/tank will not meet the requirement for “some form of liquids/solids separation” above for treatment plants where total recycle return rates exceed 10%.
The requirements to monitor the recycle stream may be reported under the respective Reporting Rule IDs with a suffix of "-recy". These are continuous monitoring requirements, which have a 1 day compliance period.
T3 protozoal rules for second stage filtration [0.5-Log]
Rule T3.50 (assurance rule)
All water passing through the treatment plant must pass through the second stage filtration process.
Compliance period: 1 year
Rule T3.51 (monitoring rule)
Turbidity must not exceed 0.1 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.52 (monitoring rule)
Turbidity must not exceed 0.3 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.53 (monitoring rule)
All of the monitoring requirements in Table 26 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Turbidity. Where it needs to be monitored: On the outlet of each filter, monitored when the filter is in service to supply. |
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Parameter: Service State. Where it needs to be monitored: Each filter. |
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Process limitations: |
A second filtration stage consists of media or granular activated carbon, other fine grain media in a separate stage after granular media filtration with preceding coagulation. |
Clarification: The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
T3 protozoal rules for slow sand filtration [2.5-Log]
Rule T3.54 (assurance rule)
All water passing through the treatment plant must pass through the slow sand filtration process.
Compliance period: 1 year
Rule T3.55 (assurance rule)
The filter must not dry out.
Compliance period: 1 year
Rule T3.56 (assurance rule)
Disinfecting chemicals must not be dosed so that they leave a residual disinfectant upstream of the filter beds.
Compliance period: 1 year
Rule T3.57 (assurance rule)
Following filter maintenance, when a filter is brought back into operation, water must be discharged to waste until the filtration process has been demonstrated to be effective.
Compliance period: 1 year
Rule T3.58 (assurance rule)
The filters must be operated at a surface loading rate of less than 0.35 m3 /m2 /h.
Compliance period: 1 year
Rule T3.59 (monitoring rule)
The temperature of the water entering the filter must not drop below 6°C at any time.
Compliance period: 1 day
Rule T3.60 (monitoring rule)
Turbidity must not exceed 0.5 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.61 (monitoring rule)
Turbidity must not exceed 1.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.62 (monitoring rule)
All of the monitoring requirements in Table 27 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Temperature. Where it needs to be monitored: Water entering the filtration stage. |
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Parameters: Turbidity. Where it needs to be monitored: On the outlet of each filter, monitored when the filter is in service to supply. |
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Parameters: Flow. Where it needs to be monitored: On the outlet of each filter. |
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Values that need to be continuously monitored: |
Surface loading rate. |
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Process limitations: |
Water treatment plants that recycle waste streams must return the recycle stream so that it undergoes the full treatment process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If flows of greater than 10% are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant inlet. |
Clarifications: Additional clarification for treatment plants with recycle streams:
- Drinking water treatment plants that have recycled waste streams must operate under T3 Treatment Rules due to the increased risk profile of recycled waste streams. To avoid doubt, recycling of waste streams cannot be done if a supplier elects to comply with T1 and T2 Treatment Rules for a drinking water treatment plant.
- Recycle waste streams (except water filtered through rapid media filters being diverted to waste) require some form of liquid/solids separation before the waste stream is returned to the plant upstream of the relevant treatment processes.
- A sedimentation basin/tank will not meet the requirement for “some form of liquids/solids separation” above for treatment plants where total recycle return rates exceed 10%.
The requirements to monitor the recycle stream may be reported under the respective Reporting Rule IDs with a suffix of "-recy". These are continuous monitoring requirements, which have a 1 day compliance period.
T3 protozoal rules for cartridge filtration [2.0-Log]
Rule T3.63 (assurance rule)
All water passing through the treatment plant must pass through the cartridge filtration process.
Compliance period: 1 year
Rule T3.64 (assurance rule)
Rapid pressure fluctuations on either side of the cartridges must be avoided. Pumps must not be connected directly to the discharge side of a cartridge filter. After filtration, the filtrate must pass to a tank if there is subsequent pumping.
Compliance period: 1 year
Rule T3.65 (monitoring rule)
Filtered water turbidity does not exceed 1.0 NTU for more than 5% of each day.
Compliance period: 1 day
Rule T3.66 (monitoring rule)
Filtered water turbidity does not exceed 1.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.67 (monitoring rule)
The filtrate turbidity from each filter housing must not exceed the turbidity of the cartridge feed water for the duration of any consecutive 15-minute period.
Note: Exceedances of not more than 2% are allowable to take account of measurement accuracy.
Compliance period: 1 day
Rule T3.68 (assurance rule)
The equipment is operated within the flow range for which it was certified at all times.
Compliance period: 1 year
Rule T3.69 (assurance rule)
Differential pressure across cartridges must be measured and kept within the manufacturer’s recommendations at all times.
Compliance period: 1 year
Rule T3.70 (assurance rule)
The minimum differential pressure must always exceed the differential pressure established at commissioning with a new cartridge and must be kept within the manufacturer’s recommendations.
Compliance period: 1 year
Rule T3.71 (assurance rule)
Individual cartridges must be able to be clearly identified in relation to the manufacturer and the part number that relates to the validation/certification.
Compliance period: 1 year
Rule T3.72 (monitoring rule)
All of the monitoring requirements in Table 28 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Turbidity. Where it needs to be monitored: On the combined inlet to the process. On the outlet of each filtration housing. |
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Parameters: Differential Pressure. Where it needs to be monitored: Across each filtration housing. |
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Parameters: Flow. Where it needs to be monitored: On the inlet or outlet of each filtration housing. |
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Parameters: Service State. Where it needs to be monitored: Each filtration unit. |
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Cartridge Validation/ Certification: |
Each cartridge must have a certified Cryptosporidium (oo)cyst removal efficiency of at least 3-log and be certified to one of the following: 1. the USEPA (2010)’s Long Term 2 Enhanced Surface Water Treatment Rule: Toolbox Guidance Manual Part 8: Bag and Cartridge Filters. 2. the (oo)cyst reduction conditions of Drinking Water Treatment Units: Health effects, NSF/ANSI 53 (NSF, ANSI 2002). 3. The (oo)cyst removal requirements of a standard recognised by Taumata Arowai as being equivalent (e.g., AS/NZS 4348:1995 in conjunction with AS/NZS 3497:1998 (updated 2001)). |
Clarification: The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
T3 protozoal rules for membrane filtration [up to 4.0-Log]
Rule T3.73 (assurance rule)
All water passing through the treatment plant must pass through the membrane filtration process.
Compliance period: 1 year
Rule T3.74 (monitoring rule)
Direct integrity tests must be performed on each membrane filtration unit at least daily (midnight to midnight) if the membrane filtration unit has been in service at any point during the day.
Compliance period: 1 day
Clarification: This rule is a monitoring rule, rather than assurance rule. The compliance period is 1 day.
Rule T3.75 (assurance rule)
No membrane unit may be used while it has failed its direct integrity test.
Compliance period: 1 year
Rule T3.76 (monitoring rule)
If the turbidity of the membrane filtrate exceeds 0.1 NTU for more than 15 consecutive minutes the membrane unit must be run to waste and not returned to supply until it has passed a direct integrity test.
Compliance period: 1 day
Rule T3.77 (monitoring rule)
Filtrate turbidity must not exceed 1 NTU at any time.
Compliance period: 1 day
Rule T3.78 (assurance rule)
If the membrane unit has been out of service for maintenance or any other reason for more than 6 hours, a direct integrity test must be completed before the unit is returned to service.
Compliance period: 1 year
Clarification: If the membrane unit has been out of service for maintenance reasons which involve physical works, a direct integrity test must be completed before the unit is returned to service. Maintenance reasons may include, dismantling of a unit, membrane pinning, installation, and replacement of units, and do not include normal operational modes like stand-by and backwashes.
Rule T3.79 (monitoring rule)
All of the monitoring requirements in Table 29 must be met.
Compliance period: 1 day
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Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Turbidity. Where it needs to be monitored: On the combined inlet to the membrane process and on the outlet of each membrane filtration unit (rack, train, or cell) when in service to supply and on any recycle streams to the plant inlet (if present). Note: where turbidity is to be monitored on the combined inlet to the membrane process, this may be source water turbidity before coagulation when membrane filtration is the only process. It may be the average of turbidity from in-service pre-treatment units |
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Parameters: Service State. Where it needs to be monitored: Each membrane filtration unit. |
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Parameters that need to be non-continuously monitored and where they need to be monitored: |
Parameters: Membrane Integrity. Where it needs to be monitored: Each membrane filtration unit. |
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Process Limitations: |
Membrane filtration includes microfiltration and ultrafiltration. Water treatment plants that recycle waste streams must return the recycle stream so that it is treated by the membrane filtration process and provide flow equalisation such that the instantaneous total return rate does not exceed 10% of the plant inflow. Turbidity monitoring is required to demonstrate that the recycle water has received effective solids/liquid separation. If flows of greater than 10% are recycled, separate treatment of the recycled stream is required to inactivate or kill protozoa and bacteria before the waste stream is returned to the plant upstream of the membranes. |
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Membrane Validation/Certification: |
Membranes must be certified to comply with NSF/ANSI 61: Drinking Water System Components – Health Effects and NSF/ANSI 419 Public Drinking Water Equipment Performance – Filtration or equivalent. The maximum number of log credits (up to a maximum of 4.0) that a membrane filtration process is eligible to receive for protozoa removal depends on third party certification of the log removal that the filter plant can deliver. The manufacturer’s certificate (or validation) must specify the operational requirements under which the membrane units must be operated to meet the specification and the integrity testing procedure that the water supplier must carry out to demonstrate that the plant is operating at the claimed log credit rating at 3-micron resolution. |
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Direct Integrity test requirements: |
The test is applied in such a manner that a 3 μm hole affects the response from the test. The test can verify the log removal value claimed for the membrane process. |
Clarifications:
The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
Additional clarification for treatment plants with recycle streams:
- Drinking water treatment plants that have recycled waste streams must operate under T3 Treatment Rules due to the increased risk profile of recycled waste streams. To avoid doubt, recycling of waste streams cannot be done if a supplier elects to comply with T1 and T2 Treatment Rules for a drinking water treatment plant.
- Recycle waste streams (except water filtered through rapid media filters being diverted to waste) require some form of liquid/solids separation before the waste stream is returned to the plant upstream of the relevant treatment processes.
- A sedimentation basin/tank will not meet the requirement for “some form of liquids/solids separation” above for treatment plants where total recycle return rates exceed 10%.
The requirements to monitor the recycle stream may be reported under the respective Reporting Rule IDs with a suffix of "-recy". These are continuous monitoring requirements, which have a 1 day compliance period.
Inactivating or killing protozoa includes processes that remove protozoa.
T3 protozoal rules for ozone disinfection [0.25 to 3.0-Log]
Rule T3.80 (assurance rule)
All water passing through the treatment plant must pass through the ozone process.
Compliance period: 1 year
Rule T3.81 (monitoring rule)
The C.t and water temperature required for the log credit claimed (Table 30) must be achieved for more than 95% of each day.
Compliance period: 1 day
Rule T3.82 (monitoring rule)
The C.t and water temperature must not be less than 80% of the values required for the log credit claimed ( Table 30) for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.83 (monitoring rule)
Turbidity must not exceed 5.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.84 (monitoring rule)
All of the monitoring requirements in Table 31 must be met.
Compliance period: 1 day
|
Log credit |
Water temperature degrees C ** |
|||||
|
1 |
5 |
10 |
15 |
20 |
25 |
|
|
0.25 |
5.8 |
4.0 |
2.5 |
1.6 |
1.0 |
0.6 |
|
0.5 |
12 |
7.9 |
4.9 |
3.1 |
2.0 |
1.2 |
|
1.0 |
23 |
16 |
9.9 |
6.2 |
3.9 |
2.5 |
|
1.5 |
35 |
24 |
15 |
9.3 |
5.9 |
3.7 |
|
2.0 |
46 |
32 |
20 |
12 |
7.8 |
4.9 |
|
2.5 |
58 |
40 |
25 |
16 |
9.8 |
6.2 |
|
3.0 |
69 |
47 |
30 |
19 |
12 |
7.4 |
* The C.t data in this table are valid for ozone concentrations in the range 0.2 - 5.0 mg/L.
** C.t values between the indicated temperatures may be determined by interpolation
|
Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: Ozone residual. Where it needs to be monitored: Water immediately before or after the contact tank. Note: Additional monitoring sites may be used in addition to the contact tank entry or exit point if the water supplier can demonstrate that they improve the accuracy of the monitoring information. |
|
Parameters: Temperature. Where it needs to be monitored: Water leaving the contact tank. |
|
|
Parameters: Turbidity. Where it needs to be monitored: Water leaving the contact tank. |
|
|
Parameters: Flow. Where it needs to be monitored: Water leaving the contact tank unless there is a high-level outlet weir in which case water entering the contact tank is acceptable. A calculated outlet flow based on inlet flow and contact level change is also an acceptable approach. |
|
|
Water level in the contact tank (if used). |
|
|
Values that need to be continuously monitored: |
T10 Contact Time. |
|
C.t (Ozone x T10 Contact Time). |
T3 protozoal rules for ultraviolet light disinfection [up to 4.0-Log as determined by the validation/certification of the reactor]
Rule T3.85 (assurance rule)
All water passing through the treatment plant must pass through the UV reactor(s) and be within the reactor’s certified flow range for at least 95% of each day.
Compliance period: 1 year
Clarification:
If any reactor fails more than 5% of the time it operates during the day, then the whole process fails for the day. Alternatively, the compliant percentage of total production volume through all UV reactors may be used to calculate whether the whole process passes/fails the 95% criteria for the day.
Rule T3.86 (monitoring rule)
The UV dose must meet or exceed that required to achieve the claimed log credit for at least 95% of each day.
Compliance period: 1 day
Clarifications:
If any reactor fails more than 5% of the time it operates during the day, then the whole process fails for the day. Alternatively, the compliant percentage of total production volume through all UV reactors may be used to calculate whether the whole process passes/fails the 95% criteria for the day.
Where UV dose is referenced in the rule, UVI may be used as an alternative depending on the validation of the UV reactors being monitored.
Rule T3.87 (monitoring rule)
The UV dose must not be less than that required to achieve the claimed log credit for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Clarification: Where UV dose is referenced in the rule, UVI may be used as an alternative depending on the validation of the UV reactors being monitored.
Rule T3.88 (monitoring rule)
Turbidity must not exceed 5.0 NTU for the duration of any consecutive 15-minute period.
Compliance period: 1 day
Rule T3.89 (monitoring rule)
UVT must meet or exceed 95% of the UVT for which the reactor has been certified for at least 95% of each day.
Note: These requirements do not apply to UV disinfection systems that automatically adjust the UV dose as the UVT of the water flowing through the reactor varies.
Compliance period: 1 day
Clarification: If any reactor fails more than 5% of the time it operates during the day, then the whole process fails for the day. Alternatively, the compliant percentage of total production volume through all UV reactors may be used to calculate whether the whole process passes/fails the 95% criteria for the day.
Rule T3.90 (monitoring rule)
UVT must not be less than 80% of the lowest UVT for which the reactor has been certified for the duration of any consecutive 15-minute period.
Note: These requirements do not apply to UV disinfection systems that automatically adjust the UV dose as the UVT of the water flowing through the reactor varies.
Compliance period: 1 day
Rule T3.91 (monitoring rule)
All of the monitoring requirements in Table 32 must be met.
Compliance period: 1 day
|
Parameters that need to be continuously monitored and where they need to be monitored: |
Parameters: UVT. Where it needs to be monitored: Water entering or leaving the UV reactor(s). Note: These requirements do not apply to UV disinfection systems that automatically adjust the UV dose as the UVT of the water flowing through the reactor varies. |
|
Parameters: Turbidity. Where it needs to be monitored: Water entering or leaving the UV reactor(s). Can include upstream filter monitoring if there is no other process between the filters and the UV reactors. |
|
|
Parameters: UVI or UV dose. For UV units certified to Ultraviolet Disinfection Guidance Manual (USEPA 2006b) monitored UVI, UVT and flow must be used to calculate dose. For UV units certified to DVGW Technical Standard W294 (DVGW 2006) or ÖNORM M 5873-1: 2020 01 01 (or UV reactors certified to öNORM M5873 (Osterreichisches Normungsinstitut 2001)) monitored flow must be used for UVI control or the reactor run at full power. UVI and UVT must be more than the validated value for the respective flow. For UV units certified to NSF/ANSI 55 Class A (NSF, ANSI n.d.); (for populations of up to 5000) – 3-log a fault must be generated when any parameter exceeds the certified value. Where it needs to be monitored: The same point in the reactor as that used for certification/validation. |
|
|
Parameters: Flow. Where it needs to be monitored: At a point representative of water entering or leaving the reactor(s). |
|
|
UVI sensor checking and standardisation: |
Duty UVI sensors must be checked at least monthly against the reference sensor. If the difference between the two readings exceeds the manufacturer’s specified limits, then the duty UVI sensor must be replaced. Reference UVI sensor must be standardised at least annually in accordance with the Ultraviolet Disinfection Guidance Manual (USEPA 2006b) or other traceable procedure. Alternatively, after 12 months the supplier can use the reference sensor as a duty sensor and purchase a new standardised sensor for use as a reference sensor. Other instrumentation must be calibrated in accordance with the instrument manufacturer’s specified procedures and frequency. |
|
UV certification/validation: |
The equipment must be certified to meet the required log credit using at least one of: 1. the Ultraviolet Disinfection Guidance Manual (USEPA 2006b) – variable log credits. 2. DVGW Technical Standard W294 (DVGW 2006). 3. ÖNORM M 5873-1: 2020 01 01. (UV reactors installed before 1 January 2020 can be certified to öNORM M5873 (Osterreichisches Normungsinstitut 2001).) 4. NSF/ANSI 55 (2019) for Class A systems (for populations of up to 5,000) – 3 log. |
Clarifications:
The reporting period for the Reporting Rule IDs associated with process limitations or certification which have a suffix of "-lmts" or "-cert", respectively, are considered assurance rules with a reporting period of 1 year.
The requirement to undertake monthly UV sensor checks has a 1 month compliance period. This should be reported under Reporting Rule IDs T3.15-sens or T3.91-sens. There is no change to the reporting period, which is 1 year.
The transition of DVGW Technical Standard W294 to DIN 19294.
A new DIN 19294-1:2020-08 Standard has been released to replace DVGW Technical Standard W294-2. The DIN 19294-1:2020-08 and ÖNORM M 5873-1:2020-01-01 are identical in content, therefore where ÖNORM M5873-1:2020-01-01 is referenced the DIN 19294-1:2020-08 will also be accepted as a suitable UV validation/certification standard.
All rules and requirements applicable to ÖNORM M5873-1:2020-01-01 apply to DIN 19294-1:2020-08.
T3 Chemical Rules
Typical Value Range
A drinking water supplier must sample the water leaving a treatment plant to determine the typical value range for specified chemical determinands to identify if any values exceed the MAV in the Drinking Water Standards and to determine the on-going monitoring frequency for those determinands.
Standard typical range refers to a determined for which sample results are always less than 50% of the MAV.
Elevated typical range refers to a determinand for which any sample exceeds 50% of the MAV but does not exceed 100% of the MAV.
In the first 12 months of monitoring,* 15 samples must be taken over a 12-month period (with no more than two samples collected in any calendar month) to determine the range of values for determinands in water leaving a treatment plant.
Values must be identified for determinands in the water leaving the treatment plant if:
- the determinand has a MAV; and
- the determinand is:
a) present in the source water at a concentration more than 50% of its MAV (as determined by the supply source water risk management plan); and/or
b) a chemical added during treatment, or a possible contaminant in a treatment chemical; and/or
c) formed as the result of a treatment process and is not expected to change in concentration beyond the treatment plant.
Following collection of the first 15 samples to establish the typical range of a determinand, the determinand must be monitored at the frequencies set out in Table 33 (see rule T3.93 below).
Some of the determinands that may arise from treatment chemicals are listed in Table 34. Drinking water suppliers must test for determinands resulting from any other treatment chemicals that they use.
|
Treatment chemical |
Determinand to monitor Monitoring is only required for treatment chemicals that are used or formed in a treatment process. |
|
Aluminium based coagulants/flocculants |
Aluminium, antimony, cadmium, copper, chromium, lead, mercury, nickel |
|
Iron based coagulants/flocculants |
Antimony, cadmium, copper, chromium, lead, mercury, nickel |
|
Polyacrylamide (polyelectrolyte) |
Acrylamide |
|
EP-DMA (polyelectrolyte) |
Epichlorohydrin |
|
Sodium hypochlorite |
Chlorate, bromate |
|
Ozone |
Bromate |
|
Permanganate |
Manganese |
If sodium hypochlorite is used, chlorate must be monitored weekly, regardless of the levels determined by sampling.
* Where coagulants are used intermittently, the water supplier must undertake an appropriate sampling programme to determine the range of values for determinands in water leaving the treatment plant.
Clarification: If sodium hypochlorite is used, sampling of chlorate must be weekly as per Table 33 unless the following qualification is met: Sampling may reduce to monthly if 12 consecutive samples are below 50% of the MAV. If a sample exceeds 50% of the MAV, sampling must return to weekly.
Rule T3.92 (assurance rule)
Values for determinands in treated water that:
- exceed 50% of their MAV in the source water, or
- are added or formed in the treatment process (as well as impurities in treatment chemicals),
must be identified by the collection and analyses of 15 samples over a 12-month period (with no more than two samples collected in any calendar month).
Compliance period: 1 year
Rule T3.93 (monitoring rule)
Determinands identified by the sampling programme outlined in rule T3.92 must be categorised as either standard typical range or elevated typical range and must be sampled at the frequency set out in Table 33.
Compliance period: 1 year
|
Minimum sampling frequency |
|||
|
Standard typical range determinands |
Elevated typical range determinands |
Chlorate |
FAC, Fluoride* |
|
Annually |
Monthly |
Weekly Sampling may reduce to monthly if 12 consecutive samples are below 50% of the MAV. If a sample exceeds 50% of the MAV, sampling must return to weekly. |
Continuous |
* If fluoride is added as part of the treatment process
Rule T3.94 (assurance rule)
Samples must be taken from a point directly after the final treatment process (including chlorine contact tanks as they are part of the treatment process).
Compliance period: 1 year
Rule T3.95 (assurance rule)
Containers used for collecting samples must be obtained from a laboratory and appropriate for the target determinand.
Compliance period: 1 year
Rule T3.96 (monitoring rule)
Event based monitoring (determined by the water supplier) must be undertaken for any event that may rapidly introduce high concentrations of health-significant chemical determinands into the water at the source or at the treatment plant.
Compliance period: 1 month
T3 Cyanotoxin Rules
Rule T3.97 (monitoring rule)
If cyanotoxins are identified in treated water, cyanotoxin testing must be undertaken in accordance with the supply cyanobacteria/cyanotoxin response plan or at least twice weekly (whichever is more frequent) until cyanotoxins are not present.
Compliance period: 1 month
Distribution System Rules
The following T3 Distribution System Rules and requirements apply.
D3 Backflow Prevention Rules
Rule D3.1 (assurance rule)
Drinking water suppliers must prepare and implement a backflow prevention programme to protect their distribution system against the risk of backflow.
Compliance period: 1 year
Rule D3.2 (assurance rule)
Periodic surveys of backflow risks to a distribution system to determine medium and high-risk sites must be undertaken by the drinking water supplier at least once every five years to assess the adequacy of backflow protection across the distribution system.
Compliance period: 1 year
Rule D3.3 (assurance rule)
Where backflow requirements at a point of supply are deemed inadequate, the drinking water supplier must notify the local authority with details of the situation and risk, determine the backflow device that should be installed at the point of supply and ensure that it is installed in a timeframe commensurate with the risk but as soon as reasonably practicable.
Compliance period: 1 year
Rule D3.4 (assurance rule)
Testing of all testable backflow prevention devices installed at a point of supply specifically to protect the network (generally boundary devices) must be undertaken, at least annually.
Note: Does not include devices that are installed downstream of the point of supply and/or within buildings that have the primary purpose of protecting building users)
Compliance period: 1 year
Rule D3.5 (assurance rule)
A drinking water supplier must maintain a register of the location of all point of supply testable backflow protection devices, device types, assessed risk level and the results of testing of all devices.
Compliance period: 1 year
Rule D3.6 (assurance rule)
Access to a water network through use of a standpipe is not permitted except by Fire and Emergency New Zealand, other emergency services, the drinking water supplier, or authorised contractors to the drinking water supplier where it is reasonably necessary to access the network for the operation of the drinking water supply.
Compliance period: 1 year
D3 New and Repaired Watermains Hygiene Procedures Rules
Rule D3.7 (assurance rule)
Before carrying out or commissioning repairs to pipes in a water distribution system, a drinking water supplier must undertake and keep records of a risk assessment to determine the risk of contamination of the network and the procedures required to minimise that risk.
Compliance period: 1 year
Rule D3.8 (assurance rule)
All materials used in construction and repairs must be free of visible contamination and remain protected from contamination until installation.
Compliance period: 1 year
Rule D3.9 (assurance rule)
All tools contacting the water supply or its parts, particularly cutting surfaces, must be adequately disinfected prior to commencing work and subsequently as necessary when tools contact soil or backfill material.
Compliance period: 1 year
Rule D3.10 (assurance rule)
Disinfection of mains (when required) must follow best management practices including but not limited to methods such as tablet, slug, spray chlorination, or equivalent as appropriate.
Compliance period: 1 year
Rule D3.11 (assurance rule)
Drinking water suppliers must develop and document standard operating procedures for planned, unplanned and emergency repairs.
Compliance period: 1 year
D3 Residual Disinfection, Disinfection By-product, and Plumbosolvent Metal Rules
Rule D3.18 (assurance rule)
A written sampling plan for determinands to be sampled in relation to disinfection, disinfection by-products and plumbosolvent metals must be prepared including a system map indicating sampling locations and response procedures to be followed when sample results do not meet prescribed levels.
Compliance period: 1 year
Rule D3.19 (monitoring rule)
A FAC of at least 0.2 mg/L must be maintained in 85% of samples (or 85% of the time if continuously monitored). Up to 15% of samples (or 15% of the time if continuously monitored) may have a FAC of less than 0.2 mg/L but must be greater than 0.1 mg/L.
Compliance period: 1 month
Clarification: For D3 Distribution System Rules, like D3.19, which may require the generation of continuous monitoring data, that data must not be interrupted for more than 3 consecutive hours in any 1 day compliance period, for compliance to be achieved.
Rule D3.20 (monitoring rule)
Samples must be collected for FAC at the frequencies outlined in Table 35.
Note: Demonstrating compliance with this rule (D3.20) is not required if FAC is continuously monitored according to rules D3.25 to D3.27.
Compliance period: 1 month
|
Distribution zone population |
Number of samples per week |
Maximum interval between samples (days) |
Minimum number of days of the week used |
|
<25,000 |
3 |
4 |
5 |
|
25,001 – 50,000 |
4 |
3 |
6 |
|
50,001 – 100,000 |
5 |
2 |
6 |
|
>100,000 |
6 |
2 |
7 |
Clarifications:
The maximum interval between samples (days) means a supplier must take the next sample before the maximum interval has elapsed.
Example: If the supplier samples on Monday at 10 am and must meet a requirement for a 2-day maximum interval between samples, then another sample must be taken before the end of Wednesday.
The minimum number of days of the week used is assessed over the course of the year and reported on in the annual report by a supplier and is not required to be met for each monthly compliance period.
It refers to the spread of sampling days in a week, i.e. weekdays and weekends, to ensure the sample represents a spread of days and trends.
Rule D3.21 (assurance rule)
Routine sampling sites must be located to adequately represent the distribution system and areas associated with higher risk of deterioration in drinking water quality and population exposure.
Note: Demonstrating compliance with this rule (D3.21) is not required if FAC is continuously monitored according to rules D3.25 to D3.27.
Compliance period: 1 year
Rule D3.22 (monitoring rule)
Analyses must be undertaken in each distribution zone according to the frequencies set out in Table 37 for the following disinfection by-products:
- trihalomethanes: chloroform, bromodichloromethane, dibromochloromethane, and bromoform; and
- haloacetic acids: dichloroacetic acid and trichloroacetic acid.
Compliance period: 1 year
|
Disinfection by- products sampling requirements |
Frequency |
|
Each distribution zone |
1 per quarter |
Rule D3.23 (assurance rule)
Sample sites for disinfection by-products must represent both peripheral and central locations in the distribution system.
Compliance period: 1 year
Rule D3.24 (assurance rule)
Analyses must be undertaken in each distribution zone for the plumbosolvent metals outlined in Table 38.
Compliance period: 1 year
|
Plumbosolvent metals |
Frequency |
|
Antimony, cadmium, chromium, copper, lead, mercury, nickel, zinc. |
Every 6 months |
D3 Facilities Operation, Maintenance and Disinfection Rules
Rule D3.12 (assurance rule)
Drinking water suppliers that have storage facilities within a distribution system must prepare a water storage management plan for the operation of storage facilities which includes the minimum and maximum operating levels, target turnover rates, inspection, and cleaning.
Compliance period: 1 year
Rule D3.13 (assurance rule)
All storage facilities must be subject to an annual security and contamination inspection and assessment by the drinking water supplier.
Compliance period: 1 year
Rule D3.14 (assurance rule)
Drinking water suppliers must prepare and use written disinfection procedures for storage facilities that are consistent with industry best management practices.
Compliance period: 1 year
Rule D3.15 (assurance rule)
All new storage facilities, and existing storage facilities that have been drained for maintenance purposes, must be cleaned and disinfected and tested for E. coli prior to being brought (back) into use.
Compliance period: 1 year
Rule D3.16 (assurance rule)
Divers’ suits, rafts, remotely operated vehicles (ROVs) and other materials used during inspection, maintenance or other activities within storage facility interiors must be made from materials acceptable for contact with drinking water and suitable for disinfection.
Compliance period: 1 year
Rule D3.17 (assurance rule)
All equipment and materials entering storage facilities must be disinfected immediately prior to entry according to industry best management practices.
Compliance period: 1 year
Alternative FAC Continuous Monitoring Rules for Distribution Systems
Water suppliers may continuously monitor FAC in a distribution zone in accordance with rules D3.25 to D3.27 as an alternative to demonstrating compliance against rules D3.20 and D3.21.
Rule D3.25 (assurance rule)
Continuous monitoring analysers for FAC must be installed in each distribution zone at the following locations:
- At a point where water is provided to a distribution zone, e.g. a reservoir outlet or bulk point of supply.
- At a supply main within the zone near to the centre or near to the extremity of the distribution zone.
Compliance period: 1 year
Rule D3.26 (assurance rule)
Continuous monitoring analysers for FAC in each distribution zone must meet the requirements set out in Table 36.
Compliance period: 1 year
|
Zone population |
Number of analysers |
|
Up to 25,000 |
2 |
|
25,001 – 100,000 |
3 |
|
>100,000 |
4 |
Rule D3.27 (assurance rule)
Confirmation of the representative nature of the continuous monitoring results must be undertaken by the collection and analysis of four FAC and pH grab samples (at least five days between samples) each month from within the distribution zone. Samples should be taken from the outer extent of the distribution zone at times of normal demand.
Compliance period: 1 year
Note: Results from confirmation sampling do not need to be reported or notified for compliance purposes.
D3 Microbiological Monitoring Rules
Rule D3.28 (assurance rule)
A written sampling plan for monitoring total coliforms, E. coli and any other determinands deemed necessary by the water supplier must be prepared, including a system map indicating sampling locations and a response plan for positive results.
Compliance period: 1 year
Rule D3.29 (monitoring rule)
E. coli and total coliforms must be monitored in each zone of the distribution system according to the frequencies set out in Table 39.
Compliance period: 1 month
|
Distribution zone population |
Number of samples per week |
Maximum interval between samples (days) |
Minimum number of days of the week used |
|
<25,000 |
1 |
9 |
5 |
|
25,001–50,000 |
1 |
9 |
6 |
|
50,001–100,000 |
2 |
5 |
7 |
|
>100,000 |
3 |
3 |
7 |
Clarifications:
The maximum interval between samples (days) means a supplier must take the next sample before the maximum interval has elapsed.
Example: If the supplier samples on Monday at 10 am and must meet a requirement for a 2-day maximum interval between samples, then another sample must be taken before the end of Wednesday.
The minimum number of days of the week used is assessed over the course of the year and reported on in the annual report by a supplier and is not required to be met for each monthly compliance period.
It refers to the spread of sampling days in a week, i.e. weekdays and weekends, to ensure the sample represents a spread of days and trends.
Rule D3.30 (assurance rule)
Routine sampling sites must be located to adequately represent water in the distribution system, including water leaving storage facilities, and entry points for water from another water supplier.
Compliance period: 1 year
Rule D3.31 (assurance rule)
Samples must be collected according to written sampling protocols prepared by the drinking water supplier or the laboratory undertaking the sample analysis.
Compliance period: 1 year
Exemptions
For some drinking water suppliers, it might be unreasonable or impractical to comply with the Act and suppliers can apply for an exemption from some requirements.
When seeking an exemption, you’ll need to tell us how the exemption will be consistent with the main purpose of the Act – ensuring that drinking water suppliers provide safe drinking water to consumers. You’ll also need to tell us how you would manage risks affecting your drinking water supply.
Head to the exemptions page for information on types of exemptions and how to apply.
This webpage is intended as a guideline and summarises legal requirements but does not address every requirement under the Water Services Act. It is not intended to be definitive and is not legal advice. Drinking water suppliers are responsible for understanding and complying with their legislative duties. The Authority may review and revise this page over time. If you are using a printed copy, please check the website to make sure it is up to date.