Below shows UK water companies and websites where you can find information about your tap water quality. The list below shows all main household water suppliers in the UK. 

Tips to Find Your Local Tap Water Quality:

  • Once you know which company supplies your address (see below for your water supplier) check their website’s water quality or water quality reports section — most publish annual test results, compliance reports, and local area results.

  • National regulators like the DWI (see link below) also link out to companies’ quality data and publish annual compliance summaries.

Large UK Water Suppliers of Drinking Water:

England and Wales

  • Anglian Water

  • Dŵr Cymru Welsh Water

  • Hafren Dyfrdwy

  • Northumbrian Water

  • Severn Trent Water

  • South West Water

  • Southern Water

  • Thames Water

  • United Utilities

  • Wessex Water

  • Yorkshire Water

  • Affinity Water

  • Bournemouth Water

  • Bristol Water

  • Cambridge Water

  • Essex & Suffolk Water

  • Hartlepool Water

  • Portsmouth Water

  • South East Water

  • South Staffs Water

  • SES Water (Sutton & East Surrey Water)

  • Cholderton & District Water Company (very small, local)

Scotland

  • Scottish Water (sole national supplier)

Northern Ireland

  • Northern Ireland Water (sole national supplier)

Official UK Water Quality & Information Websites

  1. Drinking Water Inspectorate (DWI) – The official regulator for drinking water quality in England & Wales; provides guidance, advice, quality standards, and local quality data links.

  2. GOV.UK Water Quality Checker – Government page with basic guidelines on tap water quality and reporting issues.

  3. DiscoverWater.co.uk – Central dashboard of water company performance data (including water quality, supply, environment and service) compiled with regulators and water sector bodies.

  4. Water UK ‘Find Your Supplier’ – Enter your postcode to identify your local water company, useful for locating the right quality reports.

  5. Drinking Water Quality Regulator for Scotland (DWQR) – Similar regulator for Scottish water quality (separate from DWI).

  6. Northern Ireland Drinking Water Inspectorate – The regulator for tap water quality in Northern Ireland (separate regime).