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The Water Services Authority – Taumata Arowai is progressively reviewing and updating its Drinking Water Quality Assurance Rules to make compliance more straightforward for drinking water suppliers, while maintaining the quality of drinking water supplied.
Taumata Arowai set a series of rules for drinking water quality, called the Drinking Water Quality Assurance (DWQA) Rules, that outline the minimum requirements for monitoring and treating drinking water. We expect suppliers to comply with the DWQA Rules and to report to us regularly to give us, and the public, assurance that their water is safe to drink.
On 1 January 2025, revised DWQA Rules for very small to medium-sized water suppliers came into effect, designed to offer clarity, flexibility and practical solutions for smaller communities. We’re now working on a review of the DWQA Rules that apply to large supplies. We’ll provide an update later in the year.
Right now, here’s what you need to know:
Refreshing the DWQA Rules for smaller communities
After a comprehensive review of the DWQA Rules for supplies that serve 500 or fewer people in 2024, we proposed a suite of changes and went out for consultation. We received 145 submissions expressing overwhelming support for the revised DWQA Rules, which took effect on 1 January 2025.
The updates ensure smaller suppliers can deliver safe drinking water, while meeting the unique challenges of their communities.
What’s new for very small communities supplies?
Very small communities (VSC) supplies serve up to 25 people, with allowances to serve up to 50 people for up to 60 days per year.
VSC rules now offer increased flexibility while addressing specific safety concerns.
There are additional requirements for planned events exceeding 50 people. During these events, VSC suppliers no longer need to meet General or Temporary Drinking Water Supply Rules. Instead, they must:
ensure the water is filtered (e.g., use cartridge filters) and disinfected (UV light or chlorination)
monitor treated water for E. coli and total coliforms in the week leading up to the event, and continue weekly testing if the event lasts longer than a week.
If the population exceeds 25 people for more than 60 days in any 12-month period, Level 1 Rules apply for the remainder of the calendar year.
There is now more flexibility with sampling and reporting requirements. Due to some impracticalities with the previous rules, changes have been made so that suppliers now have greater flexibility in the time between sample collections and are free to choose whether they share results with individuals connected to the supply.
Suppliers must notify the Taumata Arowai if the drinking water is, or may be, unsafe or if it does not comply with Aotearoa New Zealand’s Drinking Water Standards.
There are proposed changes to legislation in the Local Government (Water Services) Bill, including that shared domestic supplies serving 25 consumers or less will be excluded from having to comply with the Water Services Act 2021. The Bill is expected to be enacted in mid 2025.
Updates for small supplies
Small drinking water suppliers (26–100 people) fall under Level 1 Rules, which have been reformatted to provide clarity about what water suppliers need to do.
Monitoring of some substances in source water (iron in surface and groundwater, and benzo[a]pyrene in roof water) is now optional unless a specific risk to the supply is identified. Suppliers should address any risks in their Drinking Water Safety Plan, potentially including regular monitoring.
When 50 per cent of the maximum acceptable value (MAV) is exceeded for any chemical, suppliers are now required to carry out additional testing at least once a year until three consecutive test results are under 50 per cent of the MAV. This change gives suppliers more flexibility to determine how often they test their source water to best manage risk.
Medium supplies simplified and streamlined
Level 2 Rules apply to medium water supplies (101–500 people). The revised DWQA Rules offer greater efficiency. There are fewer DWQA Rules that need to be reported on annually. Annual assurance and quarterly monitoring reports (submitted within 20 working days) make compliance easier.
Treatment Rules have been simplified from 25 rules to 10, but the requirements remain similar.
Supporting suppliers with guidance
To help suppliers adapt to these changes, Taumata Arowai is preparing a range of guidelines, which it expects to release soon. This will include guidance on monitoring for chemicals in source water, cyanobacteria management, and best practice for operating UV treatment devices, backflow and reporting requirements.
You can find out more at taumataarowai.govt.nz/ by clicking ‘For water suppliers’ and viewing Standards, Rules, and Aesthetic Values.
What’s next? Reviewing the Rules for large supplies and more
In 2025, we’ll review the DWQA Rules for supplies that serve more than 500 people (large supplies). We’ll be engaging with the sector about this in the coming months.
By refining the DWQA Rules and providing tailored support, Taumata Arowai is seeking to empower suppliers to deliver safe, high-quality drinking water across Aotearoa New Zealand.
Taumata Arowai is also aiming to progress a number of priorities that will bring more clarity and certainty to the sector. Most significant on our agenda is developing and consulting on new nationally consistent wastewater environmental performance standards. The new wastewater standards will be in place later this year, and will provide efficiencies in terms of time and cost, bring greater standardisation of public infrastructure, and have the potential to save councils – and ratepayers – millions of dollars.
In addition, we are engaging actively with consumers and suppliers of mixed-use rural drinking water schemes to identify cost-effective treatment solutions that will deliver safe water to rural communities in a practical and affordable way.