Te aroturuki i te kounga wai,
Monitoring water quality

What is water quality monitoring, and what monitoring and reporting are drinking water suppliers required to do?

The Drinking Water Quality Assurance Rules (the Rules) set minimum requirements for treatment of drinking water and monitoring and reporting on drinking water supplies. This includes testing water samples and ensuring that systems, processes, and monitoring equipment are working effectively. 

The Drinking Water Standards, Drinking Water Quality Assurance Rules, andAesthetic Valueswere published and came into effect on 14 November 2022. Since then, we have also published rule clarifications to help clarify some of the interpretations of the Rules. If you notice any inconsistencies with the Rules or rule clarifications, please let us know at info@taumataarowai.govt.nz. 

Your responsibilities

All registered drinking water suppliers must ensure the water they supply is safe and that it complies with legislative requirements. This includes the reporting requirements of the Rules. The guidance provides additional detail on how you can report according to requirements with the Rules.

Reporting is only required on a limited amount of the monitoring data  you collect. Reporting requirements are determined by your supply characteristics and the Rule modules you demonstrate compliance against. The Rules set out the minimum requirements based on supply type and population served. There are 2 kinds of rules to be aware of.

  • Monitoring rules are based on monitoring water quality. These are used to determine if limits are being met using grab samples, continuous monitoring equipment, or any other means necessary.
  • Assurance rules require reporting on activities designed to measure effects of processes and monitoring procedures.

We depend on good information from you to help ensure everyone in New Zealand has access to safe drinking water every day. You are responsibile for ensuring the information you provide is complete and accurate.

You need to review your registration details in Hinekōrako and keep them up to date before submitting reporting data. Your registration details may be used to assess compliance with aspects of legislation, including for compliance with the Rules. You must assess if each rule has been achieved and report a true/false outcome accordingly. If you have a question on whether you have complied with a rule, contact us for clarification. Some examples are provided in the guidance.

Rule modules and reporting requirements

The Rules consist of rule modules and sets of rules within each of those modules.

Reporting requirements are organised by rule module in the first five General Rules. Some rules do not need to be reported against. Most rules must be reported against either monthly, quarterly, every six months, or annually as set out in the General Rules module. The following is a summary of reporting requirements by rule module.

  • Supplies following level 3 modules (serving >500 people) report monthly within 10 working days of the end of each month. See rule G3 and tables 5, 6, and 7 in the Rules.
  • Supplies following level 2 modules (serving 101 – 500 people) report quarterly within 20 working days of the end of each quarter. See rule G2 and table 4 in the Rules.
  • Supplies following level 1 modules (serving 26 – 100 people) report every 6 months within 20 working days of the end of June and the end of December. See rule G1 and table 3 in the Rules.
  • Supplies following level 1, 2, and 3 modules report annually within 40 working days of the end of each calendar year on certain matters. See rules G4 and G5 in the Rules. Note: Rule G5 does not stipulate 'working' days, but suppliers may interpret 'within 40 days' to be 'within 40 working days'.

A summary of reporting requirements for monitoring rules and assurance rules is provided in the table below for all rule modules.

Rule Module/s

Monitoring Rules Reporting Required

Assurance Rule Reporting Required

VSC (Very Small Communities)



WC (Water Carrier Services)

Not applicable


TDWS (Temporary Drinking Water Supplies)



VP (Varying Population)


Not applicable

S1, T1, D1 (Level 1 Modules)


  • 6 monthly reporting (Rule G1)
  • Annual reporting (Rule G4)


G, S2, T2, D2 (Level 2 Modules)


  • Quarterly Reporting (Rule G2)
  • Annual reporting (Rule G4)

Yes, annually (Rule G5)

Note: All applicable assurance rules for a supply using G, S2, T2, and D2 rule modules.

G, S3, T3, D3 (Level 3 Modules)


  • Monthly Reporting (Rule G3)
  • Annual Reporting (Rule G4)

Yes, annually (Rule G5)

Note: All applicable assurance rules for a supply using G, S3, T3, and D3 rule modules


Guidance on Rules reporting

The Drinking Water Quality Assurance Rules - Guidance for Reporting provides detailed information on reporting requirements, including what data you need to report and how you can report it as well as an overview of technology requirements for reporting. It also includes links to excel templates you may need for reporting if you are not using Infrastructure Data or WaterOutlook.

This guidance should be read with the Rules and rule clarifications.

You may also find the following webinars helpful: