Mixed-use rural supply

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For drinking water suppliers and operators

Information for suppliers of water via a network where at least 50% is for agricultural or horticultural use and less than 50% is for domestic use.

Key things you need to know as a provider of a mixed-use rural drinking water supply can be found on this page.

Do I provide a mixed-use rural supply?

You provide a mixed-use rural drinking water supply if:

your scheme supplies water through a network to other properties or to another drinking water supplier, and 
at least 50% of the water you supply is used for agriculture or horticulture, and  
less than 50% of the water you supply is used for domestic purposes (including for drinking water).

These schemes go by a number of different names, including ‘rural water supplies’ and ‘rural water schemes.’

Not you? Find out what type of supply you provide here.

Register with us

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 Hinekōrako - our self-service supply portal. The portal enables you to share important information with us about your supply.

Head to the registration page for more information and to access the portal.

Providing safe drinking water with an Acceptable Solution

The Water Services Act 2021outbound places a legal obligation on registered drinking water suppliers to provide water to the people connected to their network that's always safe to drink.

As a mixed-use rural supplier, you can use an Acceptable Solution to meet that obligation.

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.

The Acceptable Solution for mixed-use rural supplies uses an end-point treatment system to make water safe to drink. The system comprises 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. An air gap or backflow prevention device is also required, 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.

Use qualified, trained or experienced people

It's important that the people who install, maintain and manage your drinking water supply are suitably qualified, trained or experienced.  Different tasks involved in water schemes will require different skills and experience.

Installing systems

A registered plumber must be used to install the end-point treatment systems if the work involves sanitary plumbing. 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 mixed-use rural 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 mixed-use rural 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 mixed-use rural 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.  End-point treatment must be used where a mixed-use rural scheme supplies water for domestic purposes, such as drinking. 

An end-point treatment system must consist of: 

at least one cartridge filter having a 5 micron or less nominal pore size, and 
an ultraviolet (UV) disinfection system that must deliver a minimum reduction equivalent dose of 40 mJ/cm².

In addition: 

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 the three points 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 mixed-use rural scheme using this Acceptable Solution (even if the water isn’t used for drinking) 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 mixed-use rural 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.

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 mixed-use rural 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 analysis 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 mixed-use rural water supply also have a responsibility to monitor the water treated by their end-point treatment system.

You are 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. 

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.

Last updated: 3 September 2025

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