Medium networked supply
Information for drinking water supplies that normally serve 101 to 500 people through a network of pipes.
Key things you need to know as a provider of a medium networked drinking water supply can be found on this page.
Register your supply
If you're a new supplier, or an existing supplier who was registered under the Ministry of Health 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.
Drinking Water Quality Assurance Rules or Acceptable Solution?
Providers of medium networked supplies have two options for complying with the Water Services Act 2021outbound and ensuring safe drinking water is delivered to their community.
You can either prepare a drinking water safety plan (DWSP) and follow the Drinking Water Quality Assurance Rules (see below) or use a readymade option called an Acceptable Solution. If you choose the Acceptable Solution, you will not need to prepare a DWSP or follow the Drinking Water Quality Assurance Rules.
Information about the Acceptable Solution is further down this page and you can jump to it here.
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 community. 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 outbound
- 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).
Some registered suppliers may not need to prepare a DWSP
You may be able to comply with an Acceptable Solution. If this is the case, you need to decide between the following options in relation to each of your supplies:
- Option 1: prepare a DWSP (including a source water risk management plan) that complies with the Water Services Act 2021outbound, and follow the Rules or
- Option 2: comply with an Acceptable Solution, which have been developed for particular supply types and circumstances.
If an Acceptable Solution doesn't apply or you choose not to use one, you must complete a DWSP.
Note: If you meet the criteria you can switch between following the Rules and following an Acceptable Solution. However, you will have to update your registration details in Hinekōrakooutbound and submit reports for the period that you are following the Rules. If you are changing from an Acceptable Solution to following the Rules you will also have to complete and upload a DWSP.
Source water 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.
Guidance and template
We've prepared additional guidance and a template you can use to submit your DWSP. It's not mandatory to use the template and you can submit your plan in a different format as long as it addresses each of the elements described under ‘What should be in a DWSP?’ above.
Guide to uploading your DWSP to Hinekōrako outbound
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.
See also this rules guidance for medium supplies.
General Rules
The following Level 2 General Drinking Water Quality Assurance Rules apply.
Rule G2.1 - reporting requirements (assurance rule)
Drinking water suppliers following level 2 monitoring rules must report quarterly:
(a) whether they complied with each monitoring rule requirement; and
(b) the number of months for which each monitoring rule requirement was not complied with during each quarter; and
(c) the supply component ID, sample ID, sample date, and test results for all samples analysed by a laboratory taken during the quarter; and
(d) within 20 working days of the end of each quarter; and
(e) in an approved form.
Compliance period: 1 year
Rule G2.2 - reporting requirements (assurance rule)
Drinking water suppliers following level 2 assurance rules must report annually:
(a) whether they complied with each assurance rule during each calendar year; and
(b) within 40 working days of the end of each calendar year; and
(c) in an approved form.
Compliance period: 1 year
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 and distribution zone identifier allocated by the Water Services Authority - Taumata Arowai when you register with us, 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
Supplies that use continuous monitoring to demonstrate compliance need to follow continuous monitoring rules G12, G13, G15, G16 and G17.
Rule G12 – continuous monitoring equipment (assurance rule)
Continuous on-line 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 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
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 (monitoring 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 Level 2 Source Water Quality Assurance Rules apply.
Rule S2.1 - surface and groundwater source monitoring (monitoring rule)
Surface and groundwater sources must be monitored:
(a) at least every month for the following:
(i) E. coli
(ii) total coliforms; and
Compliance period: 1 month
(b) at least annually for the following:
(i) pH
(ii) turbidity
(iii) iron
(iv) manganese
(v) nitrate
(vi) arsenic
(vii) boron.
Compliance period: 1 year
Rule S2.2 - roof water source monitoring (monitoring rule)
Roof water sources must be monitored:
(a) at least every month for the following:
(i) E. coli
(ii) total coliforms; and
Compliance period: 1 month
(b) at least every 3 years for the following:
(i) cadmium
(ii) copper
(iii) lead.
Compliance period: 1 year
Rule S2.3 - chemical determinands (monitoring rule)
Any chemical determinands that are identified as presenting a risk to the supply or are found to exceed 50% of their MAV in source water samples must be monitored at least annually until 3 consecutive results from source water samples are less than 50% of the MAV.
Compliance period: 1 year
Rule S2.4 - collection points (non-reporting rule)
Samples collected under:
(a) rule S2.1 must be collected at the abstraction point or treatment plant prior to treatment and/or mixing with other sources; and
(b) rule S2.2 must be collected at the raw water storage tank outlet and prior to any treatment.
Rule S2.5 - cyanobacteria risk (assurance rule)
Water sources must be categorised as either no, low, medium or high risk for the presence of cyanobacteria.
Compliance period: 1 year
Rule S2.6 - cyanobacteria risk (non-reporting rule)
The following measures must be taken in relation to surface water intakes:
(a) Each month between October and May (inclusive):
(i) the water and area around and upstream of the intake must be visually inspected for the presence of benthic cyanobacteria mats and planktonic cyanobacterial growth; or
(ii) water must be monitored for cyanobacterial cell count at the treatment plant prior to mixing and treatment.
(b) If there is evidence of cyanobacterial growth, steps must be taken to evaluate the cyanotoxin risk to consumers.
(c) If there is a risk of supplying water with cyanotoxins that exceed MAVs, abstraction of water must be discontinued, an alternative source used, or treatment installed, until the risk is no longer present.
Rule S2.7 - taste and odour complaints (assurance rule)
Consumer taste or odour complaints, which have the potential to relate to cyanobacteria, must be:
(a) recorded; and
(b) investigated to determine the cause.
Compliance period: 1 year
Treatment Rules
The following Level 2 Treatment Quality Assurance Rules apply.
Rule T2.1 - monitoring requirements (monitoring rule)
Water leaving a treatment plant must be monitored at least every month for the following:
(a) E. coli
(b) total coliforms
(c) any chemical used in the treatment process (Fluoride and FAC have separate requirements, see rule T2.2).
Compliance period: 1 month
Rule T2.2 - monitoring requirements (monitoring rule)
Water leaving the treatment plant must be monitored at least 8 times per month for the following:
(a) turbidity
(b) FAC (not required for self-supplied buildings)
(c) pH (not required for self-supplied buildings)
(d) fluoride (only if added to the water).
Compliance period: 1 month
Rule T2.3 - monitoring requirements (non-reporting rule)
Samples collected for rule T2.2 must:
(a) be evenly spaced across each month; and
(b) use at least 3 different days of the week within each month.
Rule T2.4 - chlorate monitoring (monitoring rule)
Water leaving a treatment plant must be monitored for chlorate at least every 3 months if sodium hypochlorite (or calcium hypochlorite) is used as a disinfectant and this solution is not generated on-site from a salt brine solution.
Compliance period: 3 months
Rule T2.5 - monitoring of additional risks (monitoring rule)
Any additional determinands which are identified as presenting a risk to the supply must be monitored at least every month in water leaving a treatment plant until 3 consecutive results from treated water samples are less than the 50% of the MAV.
Rule T2.6 - plant water limits (assurance rule)
Water leaving a treatment plant must meet the following limits while the plant is in production:
(a) Turbidity must be less than 5 NTU.
(b) FAC must be at least 0.5 mg/L (not required for self-supplied buildings).
(c) pH must be between 6.5 – 8 (not required for self-supplied buildings).
Compliance period: 1 year
Rule T2.7 - water filtering (assurance rule)
All water, excluding groundwater abstracted from a depth of greater than 30 metres, must be filtered by a:
(a) cartridge filter system that includes a 5 micron (nominal) or smaller pore size; or
(b) back-washable media filter; or
(c) slow sand (biological) filter; or
(d) membrane filter.
Compliance period: 1 year
Rule T2.8 - cartridge filtration (assurance rule)
If cartridge filtration is used:
(a) the final cartridge must have a pore size of 5 microns (nominal) or less; and
(b) pumps must not be connected directly to the discharge side of any cartridge filter; and
(c) where pumping occurs after filtration, the filtrate must first discharge directly to a tank; and
(d) differential pressure must be measured across each cartridge filter and must not exceed the cartridge filter manufacturer’s specifications; and
(e) the flow through any filters must be within the manufacturer’s design specifications for the treatment processes at all times.
Compliance period: 1 year
Rule T2.9 - disinfection (assurance rule)
All water supplied to consumers must be:
(a) disinfected with UV light; and
(b) disinfected with chlorine.
Compliance period: 1 year
Rule T2.10 - UV treatment (assurance rule)
The following requirements must be met for UV treatment:
(a) UV units must provide at least 40 mJ/cm2 (or equivalent) reduction equivalent dose (RED) of UV light:
(b) UVT must be monitored monthly or continuously:
(c) UVI or UV dose must be recorded twice weekly or monitored continuously:
(d) UV units must be certified to (and operate within the specifications of) at least one of the following:
(i) NSF/ANSI 55 Class A (NSF, ANSI n.d):
(ii) Ultraviolet Disinfection Guidance Manual (USEPA 2006b):
(iii) DVGW Technical Standard W294 (DVGW 2006):
(iv) ÖNORM M 5873-1: 2020 01 01; or ÖNORM M5873 (Osterreichisches Normungsinstitut 2001):
(v) DIN 19294-1:2020-08:
(e) water flowing through the UV unit/s must:
(i) meet the limits of UVT specified by the manufacturer; and
(ii) be restricted or monitored so that the flow rate does not exceed the flow rate specified by the manufacturer:
(f) lamp usage must:
(i) be recorded; and
(ii) be alarmed if the UV unit has more than one lamp; and
(iii) not exceed manufacturer's recommendations:
(g) the duty UVI sensor must:
(i) be referenced against a new sensor annually; and
(ii) be replaced if the duty sensor reads levels different to the new sensor that are outside the manufacturer’s recommendation.
Compliance period: 1 year
Distribution System Rules
The following Level 2 Distribution System Quality Assurance Rules apply.
Rule D2.1 - monitoring requirements (monitoring rule)
Water in each distribution zone must be monitored at least every month for the following:
(a) E. coli
(b) total coliforms.
Compliance period: 1 month
Rule D2.2 - monitoring requirements (monitoring rule)
Water in each distribution zone must be monitored at least 8 times every month for FAC.
Compliance period: 1 month
Rule D2.3 - sampling points (non-reporting rule)
Samples for FAC, E. coli and total coliforms must be taken at regular sampling points that are representative of the geographical coverage of each distribution zone including:
(a) exit points of storage reservoirs/tanks; and
(b) end points of the distribution zone.
Rule D2.4 - monitoring for FAC (non-reporting rule)
Monitoring for FAC in each distribution zone must:
(a) be evenly spaced across each month; and
(b) use different days of the week.
Rule D2.5 - monitoring requirements (monitoring rule)
Water in each distribution zone must be monitored at least annually for:
(a) antimony
(b) cadmium
(c) chromium
(d) copper
(e) lead
(f) mercury
(g) nickel.
Compliance period: 1 year
Rule D2.6 - sampling points for metals (non-reporting rule)
When sampling for metals, sample points must:
(a) be flushed immediately prior to obtaining samples; and
(b) not be disinfected, e.g. flamed, immediately prior to sampling for metals; and
(c) be located near the end point of the system.
Rule D2.7 - FAC levels (assurance rule)
FAC in each distribution zone must be:
(a) at least 0.2 mg/L in 80% of samples taken; and
(b) no less than 0.1 mg/L at all times.
Compliance period: 1 year
Rule D2.8 - backflow risk (assurance rule)
The following measures must be taken in relation to backflow:
(a) Each distribution zone must be assessed for backflow risks and cross-connections at least annually.
(b) A register of all connections where there is a medium or high backflow risk must be maintained.
(c) A suitable backflow prevention device must be installed at any connection identified in the register.
(d) Every testable backflow prevention device must be inspected and tested annually by a suitably trained and qualified person.
(e) Any faulty backflow prevention device must be remediated as soon as practicable.
(f) Records of backflow prevention device test results must be retained for at least 3 years.
Compliance period: 1 year
What if my population varies?
The Rules described above apply to a usual population of 101 to 500 people on your drinking water network. However, many supplies serve larger populations for short periods (e.g. during holiday periods or when an event is being held).
If such periods do not exceed 60 days (in total) during any 12-month period, you can continue to follow the Rules for a medium networked supply, but you will need to follow additional Rules during the period(s) of increased population. The additional Rules are detailed below.
If your population exceeds 500 people for more than 60 days during any 12-month period, you'll need to follow the Rules for large networked supplies.
Varying population rule VP3 – monitoring requirements (non-reporting)
If a supply operating under level 2 treatment rules exceeds 500 people, the water leaving the treatment plant must be additionally monitored:
(a) at least weekly for:
(i) E. coli
(ii) total coliforms; and
(b) at least daily for:
(i) turbidity
(ii) FAC
(iii) pH.
Varying population rule VP4 – monitoring requirements (non-reporting)
If a supply operating under level 2 distribution rules exceeds 500 people, water in each distribution zone must be additionally monitored:
(a) at least weekly for the following:
(i) E. coli
(ii) total coliforms; and
(b) at least daily from a range of sites across each distribution zone for FAC.
Acceptable Solution
You might choose to use an Acceptable Solution to ensure safe drinking water is provided to your community and show compliance with the Water Services Act 2021outbound.
An Acceptable Solution is a readymade method of demonstrating legal compliance with particular sections of the Act. If you use the Acceptable Solution described below you will not need to prepare a drinking water safety plan or follow the Drinking Water Quality Assurance Rules above.
The Acceptable Solution for small to medium networked supplies uses an end-point treatment system to make water safe to drink. The system is made up of cartridge filters to remove dirt and other suspended particles from the water and a UV treatment system to control microorganisms such as bacteria and viruses. The Acceptable Solution also requires that an air gap or backflow prevention device is used to stop potentially contaminated water from flowing back into the drinking water supply.
View the full Acceptable Solution here. The key requirements are summarised below.
Choosing between the Acceptable Solution and the Rules
If you choose to use an Acceptable Solution, you:
|
Do need to |
Don’t need to |
|
|
There are factors that drinking water suppliers can consider to help them choose between following an Acceptable Solution or preparing a drinking water safety plan and following the Rules. These factors include:
- the cost of multiple end-point treatment systems versus a single centralised treatment system
- the stability of your population – is it likely to increase above the thresholds for an Acceptable Solution noted in the table above?
- the practicality of installing end-point treatment systems
- the availability of qualified, trained or experienced people to install, operate and maintain the treatment system
- the availability of people to meet the greater reporting requirements of the Rules
- the suitability of your source water (see below).
Use qualified, trained or experienced people
It's important that the people who install and maintain your end-point treatment system, monitor your source water and manage your operations are suitably qualified, trained or experienced. Different tasks will require different skills and experience.
Installing systems
A registered plumber must be used to install end-point treatment systems if sanitary plumbing work is involved. The systems must be installed in accordance with the manufacturer's instructions.
Monitoring water
The monitoring of source water, particularly in supplies at risk from cyanobacteria, is a very important role (see ‘Suitable source water is critical’ below).
No specific qualifications currently apply to this role. However, availability and local knowledge are fundamentally important. We suggest that you consider making this a shared role, especially at times when the risk of flooding or cyanobacteria blooms is higher.
The people monitoring the quality of your source water should take a cautious approach and be willing to call on expert advice when they are unsure.
Managing operations
The equipment used to operate a water scheme can vary in complexity, so the person or people who operate your scheme should have a corresponding level of experience and knowledge. Operators should be willing to seek expert assistance when required and ensure they gain the required training.
Suitable source water is critical
Groundwater from a bore or spring or surface water from rivers, lakes, streams or open irrigation channels can be used as source water under the small-medium networks Acceptable Solution.
Good end-point treatment starts with good source water. If the quality of the water coming into the end-point treatment system is low, the system may not work properly and it may not be possible to make the water safe to drink.
Generally, groundwater is better suited to end-point treatment than surface water. Surface water sources are at much greater risk of experiencing problems that can reduce the effectiveness of end-point treatment and place the health of consumers at risk.
Factors affecting the quality of source water:
- Turbidity – the haziness or cloudiness of water – is caused by the presence of fine suspended particles such as soil and organic matter. If turbidity is high, it can affect UV transmittance and reduce the effectiveness of UV treatment. High turbidity can also reduce the effectiveness of disinfectants such as chorine and cause filters to block.
- The turbidity in your source water must be low enough to ensure filters will last at least a month before needing replacement.
- UV transmittance must be high enough that the UV dose reaches pathogens that may be in the water.
- High quantities of manganese and iron in the water can also interfere with UV treatment systems by coating the UV sleeve.
- Chemicals such as nitrate and arsenic in the water cannot be removed and if present in high enough concentrations can endanger the health of consumers. Chemical levels in your source water must not exceed the Maximum Acceptable Values (MAVs) shown in the Drinking Water Standardsoutbound.
You’ll need to monitor all these factors to determine whether the source water is suitable for the small-medium networks Acceptable Solution or whether following the Rules is the better option.
You’ll also need to monitor regularly once the Acceptable Solution is in place (see ‘Monitoring the water in your network’ below). All chemical and microbiological monitoring must be undertaken by an accredited laboratory according to the lab’s instructions.
Cyanobacteria risk in surface water sources
Microscopic organisms called cyanobacteria are commonly found in surface water and can present a significant risk to drinking water. Cyanobacteria themselves are not dangerous to health. However, under some circumstances, some cyanobacteria can release cyanotoxins that can be very harmful to human and animal health.
Cyanobacteria are often referred to as ‘blue-green algae’ and may form colonies referred to as ‘algal blooms’.
If you’re sourcing your water from a lake, river or other surface water source, you must inspect the water and surrounding area each month (from October to May) for signs of cyanobacterial growth (like mats or blooms). If you see any signs, you’ll need to assess whether there’s a toxin risk and, if so, develop and follow a response plan.
If you or anyone else drinking from your supply is concerned about the taste or odour of the water (particularly an earthy or musty smell or taste), which may relate to cyanobacteria, you must investigate it.
Protection for springs or bores
Where water is sourced from a spring or bore, the following requirements must be met under the small-medium networks Acceptable Solution:
- Springs and bores must be protected by headworks that minimise the risk of contamination from nearby surface water.
- Farm animals must be excluded from an area extending at least five metres in all directions from the headworks of a bore, spring or spring-fed pond.
- In addition, springs and bores must not be affected by contamination from any of the following:
- A sewage disposal field or effluent discharge (for example, a septic tank or other wastewater treatment system).
- An underground storage tank (such as those used at a petrol station).
- A waste pond.
- A landfill.
- An offal pit.
- Areas where pesticides or animal effluent are applied to land.
- Aquifers contaminated with, or at risk of contamination with, sewage from exfiltration and/or pump station overflows.
- Other contaminated sites.
Springs and bores that provide geothermal water cannot be used as source water under this Acceptable Solution. If you’re sourcing water from a spring or bore you should also familiarise yourself with any relevant requirements that your regional council has.
Pre-treatment of water
Pre-treatment of source water before it enters the end-point treatment system may be needed for some source waters but is not compulsory for all sources. Pre-treatment might include reduction of turbidity or the addition of chlorine to control microorganisms.
While pre-treatment is not required to meet the water quality requirements of this Acceptable Solution, it may be necessary to provide consistently suitable water – particularly in schemes using surface water that might be subject to high turbidity.
Requirements of the end-point treatment system
End-point treatment is where the water is treated to make sure it’s safe to drink at the end of the pipe near where the water is consumed.
An end-point treatment system must consist of:
a) at least one cartridge filter having a 5 micron or less nominal pore size, and;
b) an ultraviolet (UV) disinfection system that must deliver a minimum reduction equivalent dose of 40 mJ/cm2
In addition:
c) water flowing through the UV disinfection system must be restricted or monitored so that the flow rate does not exceed that specified by the manufacturer for a UV reduction equivalent dose of 40 mJ/cm2 of UV light, and lamp usage in the UV disinfection system must not exceed the manufacturer's recommendations.
Written evidence must be available (for example, from the manufacturer’s website, or the instruction manual) confirming points b. and c. above. A validated system (see below) will meet these requirements.
In addition, each component of an end-point treatment system must be installed in such a way that it can meet the peak instantaneous demand for treated drinking water at the connected property and must be installed, operated and maintained in accordance with the manufacturer’s instructions and requirements.
When considering purchase of an end-point treatment unit, we recommend using a reputable end-point treatment equipment supplier to ensure the 5 micron and 40 mJ requirements are met.
Backflow prevention
Backflow prevention devices must be installed at every connection to the supply.
Backflow can let contaminated water back into your system, so every property connected to a network using this Acceptable Solution must have one of the following:
- An air gap, or
- A non-testable dual check valve, or
- A non-testable double check valve, or
- A testable backflow prevention device.
If a property has a medium or high backflow risk, they must use a testable device. Air gaps and testable devices must be inspected annually.
Population limits on an end-point treatment system
You can supply more than one household or building using a single end-point treatment system. However, there are limits on how many people and/or buildings can be served by a single system.
Supply to a single building
If one end-point treatment system supplies drinking water to a single building on a consumer’s property, such as an apartment building or a packing shed, the base population of that building must not exceed 500 people.
However, the number of people in a building might vary from time to time (for example, the base population might increase significantly over the summer holidays). The small-medium networks Acceptable Solution allows for such variability. The base population limit can be exceeded for a total of no more than 60 days in any 12-month period.
This exceedance can happen only if the end-point treatment system has the capacity to effectively treat drinking water for the number of people using it during the periods of increased population.
Supply to more than one building
A single end-point treatment system may also provide drinking water to two or three buildings on one property or adjoining properties with common ownership arrangements, where the base population does not exceed 100 people in total.
Common ownership arrangements include:
- an apartment building with a residential body corporate where multiple people own unit titles but manage the common property together
- Māori land which may be artificially divided into separate titles but treated in reality as one property
- a rural school where the Ministry of Education owns neighbouring houses for staff accommodation that are on a separate title
- commercial suppliers who own multiple property titles operated on one industrial site.
Contact us if you’re unsure whether your property can be categorised as under common ownership arrangements.
If these population limits are exceeded, compliance could be achieved by using more than one end-point treatment system.
Validated and unvalidated UV treatment systems
Before the changes introduced by the Water Service Authority – Taumata Arowai in 2025, only end-point treatment devices that had been validated or certified to one of four international standards (referred to as ‘validated’ units) could be used under an Acceptable Solution. Validation requires that a unit provides some form of alarm or notification to consumers if UV treatment is ineffective.
However, this requirement increased the complexity and cost of end-point treatment systems and was consequently reviewed.
Under the small-medium networks Acceptable Solution introduced in 2025, validated systems are still required if:
- the base population of any connected property exceeds 25 people, or
- the treatment system is supplying drinking water to the public (for example, at cafés, marae, schools, community halls and campgrounds). Note that population limits (see above) still apply.
Unvalidated systems can be used at consumer properties with fewer than 25 people that do not serve a community purpose or the public (for example, a small workplace such as a farm building with under 25 staff).
Unvalidated units still have to meet the basic requirements including written confirmation the system can deliver at least 40 mJ/cm2 reduction equivalent dose of UV light.
Premises such as schools, community halls, sports clubs, cafes and campgrounds must use a validated unit no matter what their base population is.
Using storage tanks
Storing water in tanks poses risks, especially from contamination by animals or their droppings. With proper care, these risks can be significantly reduced.
If people connected to your water supply are using storage tanks to hold drinking water, one of your requirements under this Acceptable Solution is to recommend to them – in writing and at least annually – that:
- treated drinking water storage tanks should be secured against rainwater and surface water getting in
- inlets, lids, overflows and any other small gaps in treated and untreated drinking water storage tanks should be secure from contamination by vermin, birds, animals, faecal material, or other material
- any treated or untreated drinking water storage tanks should be inspected annually to ensure the above are met
- untreated water from any other source should be first delivered into an untreated water storage tank so that all water to be used for drinking passes through the end-point treatment system.
Informing property owners connected to your supply
If you’ve required the owner of a property connected to your supply to install, maintain and test an end-point treatment device, you’ll need to inform them in writing, at least annually, of:
- the minimum requirements for the end-point treatment device that must be installed to meet the requirements of this Acceptable Solution (see ‘Requirements of the end-point treatment system’ above)
- the maintenance requirements for each component of the end-point treatment device (for example, changing UV lamps and cartridge filters), and
- the testing or monitoring requirements to verify that the end-point treatment device is operating correctly (see ‘Monitoring by consumers’ below).
Monitoring the water in your network, reporting the results and record-keeping
You’re required to monitor the water in your network at least every 3 months for:
- microbiological content: E. coli, total coliforms
- physical properties: turbidity, UV transmittance.
You’re also required to monitor at least once a year for:
- chemical content: iron, manganese, nitrate, arsenic, boron, hardness and any other chemicals that are identified as presenting a risk to the supply.
All chemical and microbiological monitoring must be undertaken by an accredited laboratory, according to the lab’s instructions Physical monitoring is generally done by hand-held on-site measuring devices.
Reporting on the results of your water monitoring
You’re also required to let the people connected to your supply know the results of all monitoring tests as soon as possible after the results are received.
This should be in writing and can be done in a number of ways. For example, you could provide a written letter or email, advise through an appropriate community messaging system such as a Facebook page or WhatsApp group, or post the results on an appropriate website.
Providing information to one person per connection is sufficient. This could be the owner of the property, a tenant, a manager of a business, a school principal, a nominated contact person or the person who pays the water bill.
Record-keeping
You’re required to keep records of information and communication relating to:
- the installation, maintenance and testing of end-point systems
- the inspection and maintenance of supply components including storage tanks, pipes and pumps
- water monitoring results
- all communication with property owners and consumers
- your emergency plans and any responses you’ve made.
These records must be kept for at least three years.
Water monitoring by consumers on your network
The people connected to your water supply also have a responsibility to monitor the water treated by their end-point treatment system.
You’re required to recommend to them in writing – at least every six months or when a property changes ownership – that they test the water treated by their end-point treatment system for E. coli and total coliforms at least every six months.
You should also recommend that if the population at their property temporarily increases beyond its base population they test their water for E. coli and total coliforms every week. This additional testing should continue throughout the period of increased population.
Preparing for an emergency
Think ahead about anything that could stop your treatment systems from working or prevent you from supplying enough drinking water for your community.
These could be natural events such as earthquakes and floods or manmade situations such as a power outage or chemical spill.
Suppliers must have a response plan for each of those situations and must follow it if an event happens.
Transitioning from an earlier Acceptable Solution
If you were meeting the requirements of an earlier Acceptable Solution (for spring and bore water or roof water sources), you have one year from 4 September 2025 (the date the new Acceptable Solutions were enacted) to start complying with this new Acceptable Solution for small-medium supplies.
You can choose to switch over to the new requirements earlier.
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.