Public water supplies

Northern Ireland Water is the public water supplier in Northern Ireland. The DWI investigates incidences where drinking water quality standards have been breached or compromised and also carries out an annual assessment of Northern Ireland Water.


You can view current and historical reports on the compliance with the drinking water quality standards using the link below:-

The following Drinking Water Quality tables provide detail of individual water supply zones where full compliance with the regulatory standards has not been met.

Enforcement Policy

If Northern Ireland Water fails to meet the required standards, the DWI may take enforcement action as detailed in the Environment, Marine and Fisheries Group Enforcement Policy:-

You can view Undertakings, agreed between NI Water and the Chief Inspector of Drinking Water, following enforcement action taken under Section 31(3)(a) of the Water Sewerage Services (Northern Ireland) Order 2006. Current and historical documents can be viewed using the links below:


The following legislation implements the requirements set out in the European Drinking Water Directive (98/83/EC), the amending Directive (EU) 2015/1787 which revised the monitoring and analysis requirements in Annex II and Annex III of Directive (98/83/EC), and Directive 2013/51/Euratom in respect of public drinking water supplies:

The Water Supply (Water Quality) Regulations (Northern Ireland) 2017

DWI also has regulatory responsibilities for drinking water quality supplied, via a domestic distribution, to the public in premises such as schools, hospitals and restaurants under:

Guidance on the Water Supply (Water Quality) Regulations (NI) 2017

Other Guidance

Directive (EU) 2015/1787

Directive (EU) 2015/1787 revised the monitoring and analysis requirements set out in Annex II and Annex III of the Drinking Water Directive. The Department is required to transpose the requirements of the Directive by 27 October 2017. A consultation paper on proposals to introduce new consolidated water quality regulations relating to the public drinking water supply in order to transpose the Directive was issued but is now closed to responses and a synopsis of responses has been published.

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