What DWI does
Regulates drinking water quality in England and Wales. Audits water companies, investigates water quality incidents, and approves products and substances used in public water supplies. Part of Defra.
Contact DWI
- Phone
- 0330 041 6501
Official guidance from DWI
Curated guidance documents to help you understand your obligations.
(FAQ5) How can I check whether a product is approved for use with drinking water supplies? - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
Notice of regulation: Northumbrian Water Limited – AMP 7 Discolouration, Multiple Zones - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
Private Supply Legislation - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
RADIOACTIVITY MONITORING OF WATER SUPPLIES - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
Treatment Guide - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
What is Reg31? - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
A complaint about a local authority not discharging its duty under the regulations - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
Action in the event of a failure at a single domestic dwelling - Drinking Water Inspectorate (opens in a new tab)
Detailed Guidance · England and Wales
View all 895 guidance documents (opens in a new tab)
Legal framework
Legislation that DWI directly enforces.
Primary legislation
Secondary legislation
Related legislation
Legislation connected to DWI’s remit but not directly enforced — establishing Acts, amendments, referenced legislation, and context.