Our data requests
We use the Environmental Information Regulations (and the Scottish equivalent) to get water quality data that water companies don't publish. Each request, and what came back, is listed below.
Drinking Water Inspectorate
Thames Water zone list, postcode-to-zone lookup and zone boundaries
Sent 18 Aug 2026 · Due 30 Oct 2026
Internal review pendingRefused 28 Aug 2026. Internal review requested 4 Sep 2026.
Thames Water
Zone list and postcode-to-zone mapping
Sent 4 Sep 2026 · Due 2 Oct 2026
Anglian Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyCambridge Water + South Staffs Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replySevern Trent
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyHafren Dyfrdwy
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replySouthern Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replySouth East Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replySES Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyAffinity Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyNorthumbrian Water + Essex & Suffolk Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyYorkshire Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyUnited Utilities
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyWessex Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replySouth West Water + Bristol Water + Bournemouth Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyDŵr Cymru Welsh Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyPortsmouth Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyScottish Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting replyNI Water
Supply zone list, zone water quality results and postcode-to-zone mapping
Sent 9 Oct 2026 · Due 6 Nov 2026
Awaiting reply
| Organisation | What we asked for | Sent | Due | Status |
|---|---|---|---|---|
| Drinking Water Inspectorate | Thames Water zone list, postcode-to-zone lookup and zone boundaries | 18 Aug 2026 | 30 Oct 2026 | Internal review pending Refused 28 Aug 2026. Internal review requested 4 Sep 2026. |
| Thames Water | Zone list and postcode-to-zone mapping | 4 Sep 2026 | 2 Oct 2026 | |
| Anglian Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Cambridge Water + South Staffs Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Severn Trent | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Hafren Dyfrdwy | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Southern Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| South East Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| SES Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Affinity Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Northumbrian Water + Essex & Suffolk Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Yorkshire Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| United Utilities | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Wessex Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| South West Water + Bristol Water + Bournemouth Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Dŵr Cymru Welsh Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Portsmouth Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| Scottish Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
| NI Water | Supply zone list, zone water quality results and postcode-to-zone mapping | 9 Oct 2026 | 6 Nov 2026 | Awaiting reply |
We'll update this page as replies arrive.