Is tap water safe to drink in Wales?
99.97% of tests in Wales met standards in 2025 (DWI).
Wales tap water quality report · 2025
Water suppliers in Wales
Each supplier's own record from its regulator, company-wide. Your postcode tells you which supplier serves your address.
Dŵr Cymru Welsh Water
Dŵr Cymru Welsh Water: at least 59 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Hafren Dyfrdwy
Hafren Dyfrdwy: at least 12 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Some published DWI figures don't reconcile or identify a company, so we've left them out; the true number may be higher. Wales overall: 99.97% of tests met standards.
Water hardness in Wales
Each supplier's hardness from the supply-zone figures it publishes. Your own zone can differ: enter your postcode above for its figure.
| Supply area | Hardness | mg/l CaCO₃ | °Clark | °dH | °fH | What the figure covers |
|---|---|---|---|---|---|---|
| Dŵr Cymru Welsh Water | Hardness:Not covered | No figure | Covers:We do not have a verified hardness figure for this area. Ask your water company for its water quality report. | |||
| Hafren Dyfrdwy | Hardness:SofttoHard | mg/l CaCO₃:37–223 mg/l | °Clark:2.6–15.6 °Clark | °dH:2.1–12.5 °dH | °fH:3.7–22.3 °fH | Covers:Range across the 17 supply zones we hold a figure for, 93% of its postcodes. Most common band: soft (76% of its postcodes). Brymbo High (supply zone) · 1 August 2025 to 31 July 2026 Source: Hafren Dyfrdwy — dated 1 August 2025 to 31 July 2026, read 1 October 2026 Mardy (supply zone) · 1 August 2025 to 31 July 2026 Source: Hafren Dyfrdwy — dated 1 August 2025 to 31 July 2026, read 1 October 2026 |
Town reports in Wales
Frequently asked questions
- Is tap water safe to drink in Wales?
- 99.97% of tests in Wales met standards in 2025 (DWI). The figure is for Wales as a whole, from the Drinking Water Inspectorate (DWI). Each water supplier's own record is on this page, and your postcode gives the record for the supplier at your address.
- Who supplies tap water in Wales?
- Dŵr Cymru Welsh Water and Hafren Dyfrdwy supply public drinking water in Wales.
- Is tap water in Wales hard or soft?
- It depends on the supplier and the supply zone: Dŵr Cymru Welsh Water: no published figure we can read; Hafren Dyfrdwy: Soft to Hard. Enter your postcode for your own zone's figure.
Sources and method
- DWI wales 2025, national compliance ↗ · 2025 · read 13 October 2026
- DWI wales 2025, Annex B ↗ · 2025 · read 13 October 2026
Contains public sector information licensed under the Open Government Licence v3.0
Data generation uk-2026-10-16-derive6