Welcome to DWI

The Drinking Water Inspectorate (DWI) was formed in 1990 to provide independent reassurance that water supplies in England and Wales are safe and drinking water quality is acceptable to consumers.


What's new?

23 June 2017

Severn Trent Water Ltd have been cautioned over the Castle Donington event (PDF 266KB) where 3,700 properties received water with elevated chlorine.

8 June

DWI meets requirements of Regulatory Policy Committee (PDF 181KB)

8 May

Information Letter 02/2017 - Further guidance on Chromium in drinking water (PDF 122KB).

13 April

The Inspectorate’s Guidance to companies in implementing the English and Welsh Water Supply (Water Quality) Regulations 2016 has been updated, for the following principal reasons:

• To refer to the Water Industry (Suppliers’ Information) Direction 2017, which took effect from 1 April 2017

• To take account of changes to water supply licensing introduced by the water Act 2014, and revocation of Combined Licenses as of 1 April 2017. The term water supplier has been introduced in various places throughout and defined in a revised footnote in the Introduction to include holders of water supply licence (wholesale and supplementary) authorisations. The terms retail-only companies and retail licensees have been replaced with “retail service providers”.

All of the documents have been updated and published as version 2, dated April 2017.

We have also taken the opportunity to amend a number of typographical errors and to make a small number of minor textual amendments to improve clarity. A paragraph has been added to Part 8 – Water treatment – Risk assessment, plumbosolvency treatment and replacement of lead pipes (Regulation 30) to refer companies to advice given in the research report Assessing the effect of water meter installation on exposure to lead in water. The new paragraph reference is 29.6.


13 February

Information letter 01/2017 – Water Industry (Suppliers’ Information) Direction 2017


Page last modified: 28 June 2017
Page reviewed: 28 June 2017

Drinking Water Inspectorate