Compliance with the Water Services Act 2021, Drinking Water Acceptable Solutions for Small and Medium Supplies.

Nov 1, 2022 | Drinking Water, Insights

“As a drinking water supply owner of small to medium size, I am sure you are aware of the various compliance pathways under the Water Services Act 2021, says Maria Johnson, Water Sector Lead at GWE Consulting Engineers. The Act applies to everyone, unless you are a domestic self-supplier, supplying water as part of your single household only.“

Before the Act, very small supplies (serving less than 25 customers and staff on a daily basis) would not have much, if any, legal requirements under the NZ Drinking Water Standards. Taumata Arowai, the new Water Services Regulator, has created a few compliance pathways to ease very small supplies into compliance and offer the most suitable compliance approach to small and medium water supplies.

More specifically;

  • The Drinking Water Quality Assurance Rules provide a straightforward set of three simple rules for very small communities (serving less than 25 people) to meet their obligations under the Act.
  • Small (26-100 people) and medium (101-500 people) supplies have the option to follow the rules category that apply best to their supply or adopt one of the three Drinking Water Acceptable Solutions;
    • For roof water supply
    • For spring and bore water supply
    • For mixed-used rural water supply (where at least 50% of the water supplied is intended for agricultural or horticultural purposes)

“These Acceptable Solutions have been designed to bring simplicity to everyone. They cover everything from design, configuration, installation, operation, maintenance, testing, monitoring, emergency management and training. It reduces the risk to supply unsafe water by removing the most common contaminants, proven to have immediate and/or long-term adverse health effects.”

The “Acceptable Solutions” is your new toolbox to comply with the Water Services Act. Photo Taumata Arowai website.

What are your compliance options as a small or medium drinking water supplier?

As a supplier serving less than 500 people, to comply with the Drinking Water Standards and Aesthetic Values 2022, you have the option to either adopt an Acceptable Solution 2022 or follow the Drinking Water Quality Assurance Rules 2022.

The Rules and Acceptable Solutions are the practical steps to comply with the Water Services Act 2021 and associated Drinking Water Standards. They set out the required treatment processes, monitoring and reporting requirements to Taumata Arowai to meet the Maximum Acceptable Values and Guidelines Values of the standards.

When choosing to follow the Rules, you will require in addition to prepare a Water Safety Plan and a Source Water Risk Management Plan. These are your supply multi-barrier risk-based management documents. You will need to implement these plans, review them continuously and submit them to Taumata Arowai.

Alternatively, to make it simple, practical, and cost effective, you can follow the acceptable solutions provided by Taumata Arowai for your specific water source if it applies. They are ready-made end-point treatment options to meet your compliance obligations based on your specific source water. The solutions have simple but effective treatment processes (made of cartridge filtration followed by UV disinfection) widely available by a range of reliable certified systems suppliers.

Let’s summarise the Acceptable Solutions for roof, spring, bore and mixed-used rural water supplies

Whether you are a small or medium drinking water supplier, your source water and treated water will be required to be tested for a range of contaminants by a laboratory that is accredited by International Accreditation New Zealand (IANZ) and listed on the Taumata Arowai register of laboratories. You will also be required to install prescribed end-point treatment processes (cartridge filtration followed by UV disinfection) and decide on what documentation are required to have in place to manage the risks to your supply. You will need to include standard operational and maintenance routines and inspection plans.

What are your base population limits?

If your supply is from spring, bore or roof water, the total base population must be no more than 500 people. For a mixed-use rural water supply, there is no upper or lower limit to the total population served. However, each end-point treatment system must only provide water to three or fewer buildings within the boundaries of one property.  

The following end-point treatment population limits apply to all Acceptable Solutions:

  • Each end-point treatment system must only provide drinking water to three or fewer buildings within the boundaries of one property.
  • The base population for a single building served by an end-point treatment system must not exceed 500 people.
  • The base population for two or three buildings served by a single end-point treatment system must not exceed 100 people (this is more restrictive than a single building due to the lack of chlorination requirement in the Acceptable Solutions).
  • The population supplied by each end-point treatment system may exceed its base population limit for a total of no more than 60 days in any 12-month period (and in which case subject to additional monitoring requirements for these periods).

What are the testing requirements?

  • If your supply is from roof water;
    • Your source(s) will need to be tested once between June and August and then every three years between June and August for benzo(a)pyrene, cadmium, copper, lead and zinc.
    • Your treated water leaving each end-point treatment system will need to be tested for E. coli and total coliforms every three months (additional testing applies when the population exceed the population limits detailed above).
  • If your supply is from a spring or bore or mixed-use rural;
    • Your source water will need to include three-monthly samples for nitrate, pH, UV transmittance, Turbidity, E. coli and total coliforms and yearly for Arsenic, Boron, Silica, Hardness, Iron and Manganese.
    • Your treated water will need to be tested every 3 months for E. coli, total coliforms and turbidity (additional testing applies when the population exceed the population limits detailed above).
  • Regardless the Acceptable Solution adopted;
    • If a monitoring result for a chemical determinand exceeds 50% of the MAV in the DWSNZ 2022, additional monitoring must be undertaken on a three-monthly basis until 4 consecutive results are less than 50% of the MAV.
    • Additional testing applies in the week prior, or otherwise as soon as reasonably practicable, when the population exceed the population limits detailed above.

“It is very straightforward and covers all the likely risks of contamination in your water. The limits for each contaminant are provided in the Drinking Water Standards. It will be very simple to identify any issue. In addition, your plans developed as part of the acceptable solution will address what to do in the case of a breach of standard or emergency.”

What are the treatment requirements?

Regardless your supply type, the Acceptable Solutions are defined as end-point treatment systems made of a two-stage cartridge filtration with 20 micron and 5 micron (or less) nominal pore sizes followed by UV disinfection. The UV disinfection must meet the minimum reduction dose of 40mJ/cm2, be continuously monitored (UV dose, flow control, lamp status, etc. as detailed in the Acceptable Solutions) and must be one of the 4 certified standards listed in the Acceptable Solutions:

  • USEPA 2006b (USA)
  • DVGW 2006 (Germany)
  • öNORM M 5873-1: 2020 01 01 (Austria)
  • NSF/ANSI n.d (USA)

“These are all readily available processes that standard suppliers will be able to install in accordance with the design, configuration and installation of the Acceptable Solutions. Your supply will be specific and there may be situations, where the Acceptable Solution cannot be adopted. In this case, the rules will be able to address your specific requirements.

A few key requirements of the Acceptable Solutions…

If your supply is from a bore or spring, you will need to ensure the installation of your headworks is secure and location and installation of your spring or bore is appropriate in regards to distancing from sewage underground storage tank, waste pond, landfill etc.  

If a treated water tank is included as part of the drinking water supply, it must be secure against ingress of rainwater and surface water. Inlets, lids, overflows, and any other small gaps in tanks must be secure from contamination by birds, animals, faecal material, or other material.

The Operation and Maintenance of your supply must be documented and recorded as detailed in the Acceptable Solutions and include incident and emergency response management and procedures.

People who maintain operate your supply must be competent to undertake tasks necessary to ensure the system provides safe drinking water and have a good understanding of the emergency and incident management procedures and how to comply with the Acceptable Solutions.

Planning your compliance

If your supply is not currently registered, you will have until 15 November 2025 to register with Taumata Arowai and until 15 November 2028 to comply with the standards by either adopting an Acceptable Solution or following the rules and preparing a Water Safety Plan.

If you are a new supply, you must register and comply before supplying water to your consumers.

If your supply was already registered prior to November 2021, you still have the option to choose your compliance pathway before 1 January 2023.

Your registration in the online service portal, Hinekõrako, will need to be renewed annually and reporting to Taumata Arowai will need to follow the rules applicable to your supply or your Acceptable Solutions requirements.

You don’t have to wait to ensure your consumers receive safer drinking water and reduce risk.

Recommendations and further Information

If you are supplying drinking water as part of your business or other private arrangement, we recommend you start investigating what compliance means for you in respect of delivering safe drinking water and complying with the new legislation. A good starting point would be the series of Drinking Water Fact Sheets, prepared by GWE that provide easy to understand information about a water suppliers duties and responsibilities under the Water Services Act 2021 and associated regulations. The Fact Sheets can be accessed by using the following link

Very small supplies rules are very straightforward and following the rules is most likely to be the most suitable compliance pathway, unless you choose to reduce the risk, in which case an Acceptable Solution is likely the simplest approach.

“The most important aspect of the reform is the safety of drinking water and managing risks. The targets for water quality haven’t changed, it’s about getting it right, consistently. Small supplies have unique challenges and options, and the best thing you can do is start early so you understand the risks and plan to make the changes for a safe and reliable water supply, says Maria.”

For further information contact,

Maria Johnson, Water Sector Leader, GWE Consulting Engineers
p. 021 288 8782

About GWE Consultants Ltd

GWE is a growth company and a leading provider of professional engineering services to the infrastructure and land/property development sectors. We specialise in environmental services, geotechnical, land development, drinking water, wastewater engineering and stormwater management. We currently have a number of opportunities for graduate, mid-career and senior engineers and scientists. To find out more visit our careers page,