National environmental standards for sources of human drinking water

They set requirements for protecting sources of human drinking water from becoming contaminated.

Official title

Resource Management (National Environmental Standards for Sources of Human Drinking Water) Regulations 2007

Lead agency

The Ministry for the Environment with support from the Department of Internal Affairs, Taumata Arowai and the Ministry of Health

In force from

20 June 2008

Proposed amendments

In early 2022 the Government consulted on proposed amendments to the NES-DW to improve the protection of human drinking water sources.

Read the consultation document from early 2022

The Ministry has since revised proposals based on feedback received during consultation and engagement to: 

  • Proposal 1: To map three categories of source water risk management area (SWRMA) — remains unchanged.
  • Proposal 2: We went out to ask questions about how best to control activities within the different SWRMAs. We propose to retain the existing protections of the NES-DW and to introduce controls for specific high-risk activities within SWRMA 1 and 2.
  • Proposal 3: Extending the protections of the NES-DW to smaller registered drinking water supplies — will not be actioned. The Ministry now intends to keep the scope of the existing NES-DW, which provides protection to source water that serves 82 per cent of the population. 

Work to progress changes to the NES-DW has been extended.

The guidelines to support mapping Source Water Risk Management Areas are now available. The mapping guidance will apply to both the existing NES-DW and any updated version.

Find out about the proposals

Why it is needed

Contaminants, such as microorganisms, pose a risk to human health when they enter drinking water supplies. Taking steps to prevent contamination of drinking water sources is part of a multi-barrier approach to reducing risks to people.

The National Environmental Standards for Sources of Human Drinking Water (NES) complements Department of Internal Affairs legislation for improving drinking water supply and delivery. This ensures a comprehensive approach to managing drinking water from source to tap.

What it does

The NES requires regional councils to ensure that activities’ effects on drinking water sources are considered in decisions on resource consents and in regional plans.

Specifically, regional councils are required to:

  • decline discharge or water permits that are likely to result in community drinking water becoming unsafe for human consumption following existing treatment
  • be satisfied that permitted activities in regional plans will not result in community drinking water supplies being unsafe for human consumption following existing treatment
  • place conditions on relevant resource consents that require notification of drinking water suppliers if significant unintended events occur (such as spills) that may adversely affect sources of human drinking water.

Sources of registered drinking water sources

A database of registered drinking water sources was established in 2009 to assist with the implementation of the NES. It contains drinking water source points and drinking water treatment plants.

The database also contains some information on individual treatment plant compliance with the Drinking Water Standards for New Zealand 2022.

The database was sent to all regional councils for integration with existing regional council GIS systems. Additional information on the locations of registered drinking water sources is available from a drinking water assessor in the public health unit of your local district health board.

Water Services (Drinking Water Standards for New Zealand) Regulations 2022 [New Zealand Legislation website]

Note, the NES, defines human drinking water sources as a natural water body (such as a lake, river or groundwater) that is used to supply a community with drinking water. The standard applies to source water before it is treated and only sources used to supply human drinking water  (and not livestock or other animals).


Find out more

Drinking Water Standards for New Zealand 2022 [Taumata Arowai website]