Tap water in England
99.97% of tests in England met standards in 2025 (DWI).
England tap water quality report · 2025
Water suppliers in England
Each supplier's own record from its regulator, company-wide. Your postcode tells you which supplier serves your address.
Affinity Water
Affinity Water: at least 20 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Anglian Water
Anglian Water group (figures include Anglian Water): at least 25 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Cambridge Water
Cambridge Water: at least 1 test failed UK drinking-water standards in 2025 (DWI, company-wide).
Essex & Suffolk Water
Northumbrian, Essex and Suffolk Water group (figures include Essex & Suffolk Water): at least 36 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Northumbrian Water
Northumbrian, Essex and Suffolk Water group (figures include Northumbrian Water): at least 36 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Portsmouth Water
Portsmouth Water: at least 2 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
SES Water
SES Water: at least 2 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Severn Trent Water
Severn Trent Water: at least 40 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
South East Water
South East Water: at least 26 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
South Staffs Water
South Staffs Water: at least 7 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
South West Water
South West and Bournemouth Water group (figures include South West Water): at least 19 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Southern Water
Southern Water: at least 24 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Thames Water
Thames Water: at least 68 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
United Utilities
United Utilities: at least 57 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Wessex Water
Wessex Water: at least 13 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Yorkshire Water
Yorkshire Water: at least 69 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. England overall: 99.97% of tests met standards.
Water hardness in England
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 |
|---|---|---|---|---|---|---|
| Affinity Water | Hardness:Slightly hardtoVery hard | mg/l CaCO₃:107–389 mg/l | °Clark:7.5–27.3 °Clark | °dH:6.0–21.8 °dH | °fH:10.7–38.9 °fH | Covers:Range across the 76 supply zones we hold a figure for, 94% of its postcodes. Most common band: very hard (52% of its postcodes). Denge (supply zone) · read on 29 September 2026 Source: Affinity Water — read 29 September 2026 Ware (supply zone) · read on 29 September 2026 Source: Affinity Water — read 29 September 2026 |
| Anglian Water | Hardness:At least slightly hard | mg/l CaCO₃:at least 115 mg/l | °Clark:at least 8.1 °Clark | °dH:at least 6.4 °dH | °fH:at least 11.5 °fH | Covers:At least 115 mg/l (slightly hard or harder) in each of the 164 supply zones we hold, 97% of its postcodes. Calcium hardness only; total hardness is higher. Woburn PWSZ (supply zone) · January 2025 to December 2025 Source: Anglian Water — dated January 2025 to December 2025, read 28 September 2026 |
| Bristol Water | Hardness:Moderately hardtoVery hard | mg/l CaCO₃:161–385 mg/l | °Clark:11.3–27.0 °Clark | °dH:9.0–21.6 °dH | °fH:16.1–38.5 °fH | Covers:Range across the 27 supply zones we hold a figure for, 100% of its postcodes. Most common band: hard (79% of its postcodes). Wells, Glastonbury, Street and Baltonsborough (supply zone) · 1 January 2025 to 31 December 2025 Source: Bristol Water — dated 1 January 2025 to 31 December 2025, read 28 September 2026 Clevedon (supply zone) · 1 January 2025 to 31 December 2025 Source: Bristol Water — dated 1 January 2025 to 31 December 2025, read 28 September 2026 |
| Cambridge Water | Hardness:Very hard | mg/l CaCO₃:304–352 mg/l | °Clark:21.3–24.7 °Clark | °dH:17.0–19.7 °dH | °fH:30.4–35.2 °fH | Covers:Range across the 7 supply zones we hold a figure for, 86% of its postcodes. Most common band: very hard (86% of its postcodes). Heydon (supply zone) · 2025 Source: Cambridge Water — dated 2025, read 20 September 2026 Odsey (supply zone) · 2025 Source: Cambridge Water — dated 2025, read 20 September 2026 |
| Essex & Suffolk Water | Hardness:HardtoVery hard | mg/l CaCO₃:230–479 mg/l | °Clark:16.1–33.6 °Clark | °dH:12.9–26.8 °dH | °fH:23.0–47.9 °fH | Covers:Range across the 30 supply zones we hold a figure for, 73% of its postcodes. Most common band: hard (59% of its postcodes). WITHAM (supply zone) · January 2025 to December 2025 Source: Essex & Suffolk Water — dated January 2025 to December 2025, read 28 September 2026 WALPOLE (supply zone) · January 2025 to December 2025 Source: Essex & Suffolk Water — dated January 2025 to December 2025, read 28 September 2026 |
| Northumbrian Water | Hardness:SofttoVery hard | mg/l CaCO₃:56–391 mg/l | °Clark:3.9–27.4 °Clark | °dH:3.1–21.9 °dH | °fH:5.6–39.1 °fH | Covers:Range across the 53 supply zones we hold a figure for, 84% of its postcodes. Most common band: slightly hard (49% of its postcodes). Gunnerton Zone (supply zone) · January 2025 to December 2025 Source: Northumbrian Water — dated January 2025 to December 2025, read 28 September 2026 New Winning & Peterlee Zone (supply zone) · January 2025 to December 2025 Source: Northumbrian Water — dated January 2025 to December 2025, read 28 September 2026 |
| Portsmouth Water | Hardness:Not covered | No figure | Covers:We are not yet printing Portsmouth Water's hardness figures while we confirm whether they describe total hardness or calcium hardness alone. | |||
| SES Water | Hardness:At least hard | mg/l CaCO₃:at least 209 mg/l | °Clark:at least 14.6 °Clark | °dH:at least 11.7 °dH | °fH:at least 20.9 °fH | Covers:At least 209 mg/l (hard or harder) in each of the 2 supply zones we hold, 1% of its postcodes. Calcium hardness only; total hardness is higher. How Green (supply zone) · 2025 operational monitoring Source: SES Water — dated 2025 operational monitoring, read 28 September 2026 |
| Severn Trent Water | Hardness:SofttoVery hard | mg/l CaCO₃:35–389 mg/l | °Clark:2.5–27.3 °Clark | °dH:2.0–21.8 °dH | °fH:3.5–38.9 °fH | Covers:Range across the 233 supply zones we hold a figure for, 95% of its postcodes. Most common band: hard (37% of its postcodes). Rubery (supply zone) · 1 August 2025 to 31 July 2026 Source: Severn Trent Water — dated 1 August 2025 to 31 July 2026, read 29 September 2026 Tickencote (supply zone) · 1 August 2025 to 31 July 2026 Source: Severn Trent Water — dated 1 August 2025 to 31 July 2026, read 30 September 2026 |
| South East 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. | |||
| South Staffs Water | Hardness:Slightly hardtoHard | mg/l CaCO₃:136–281 mg/l | °Clark:9.6–19.7 °Clark | °dH:7.6–15.7 °dH | °fH:13.6–28.1 °fH | Covers:Range across the 28 supply zones we hold a figure for, 93% of its postcodes. Most common band: moderately hard (45% of its postcodes). Walsall Central (supply zone) · 2025 Source: South Staffs Water — dated 2025, read 20 September 2026 Winshill (supply zone) · 2025 Source: South Staffs Water — dated 2025, read 20 September 2026 |
| South West 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. | |||
| Southern 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. | |||
| Thames Water | Hardness:See statement | No figure | Covers:“all the water in our region is hard” (Thames Water; Thames Water, company-wide). Thames Water, company-wide · read on 26 September 2026 Source: Thames Water — dated 26 September 2026, read 26 September 2026 | |||
| United Utilities | Hardness:SofttoHard | mg/l CaCO₃:8–285 mg/l | °Clark:0.6–20.0 °Clark | °dH:0.4–16.0 °dH | °fH:0.8–28.5 °fH | Covers:Range across the 215 supply zones we hold a figure for, 94% of its postcodes. Most common band: soft (76% of its postcodes). Bridge End (supply zone) · 12-month average, updated 25 September 2026; 14 samples Source: United Utilities — dated 12-month average, updated 25 September 2026, read 28 September 2026 Grange (supply zone) · 12-month average, updated 25 September 2026; 10 samples Source: United Utilities — dated 12-month average, updated 25 September 2026, read 28 September 2026 |
| Wessex Water | Hardness:Not covered | No figure | Covers:We are not yet printing Wessex Water's hardness figures, because we have not been able to read the figures it publishes on its own website. | |||
| Yorkshire Water | Hardness:SofttoVery hard | mg/l CaCO₃:18–371 mg/l | °Clark:1.2–26.0 °Clark | °dH:1.0–20.8 °dH | °fH:1.8–37.1 °fH | Covers:Range across the 122 supply zones we hold a figure for, 89% of its postcodes. Most common band: soft (36% of its postcodes). Skipton and Craven 2015 (supply zone) · 1 January 2024 to 31 December 2024 Source: Yorkshire Water — dated 1 January 2024 to 31 December 2024, read 29 September 2026 Hull Central West 2024 (supply zone) · 1 January 2024 to 31 December 2024 Source: Yorkshire Water — dated 1 January 2024 to 31 December 2024, read 29 September 2026 |
Town reports in England
Frequently asked questions
- Is tap water in England safe to drink?
- 99.97% of tests in England met standards in 2025 (DWI). The figure is for England 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 England?
- Affinity Water, Anglian Water, Cambridge Water, Essex & Suffolk Water, Northumbrian Water, Portsmouth Water, SES Water, Severn Trent Water, South East Water, South Staffs Water, South West Water, Southern Water, Thames Water, United Utilities, Wessex Water and Yorkshire Water supply public drinking water in England.
- Is tap water in England hard or soft?
- It depends on the supplier and the supply zone: Affinity Water: Slightly hard to Very hard; Anglian Water: At least slightly hard; Bristol Water: Moderately hard to Very hard; Cambridge Water: Very hard; Essex & Suffolk Water: Hard to Very hard; Northumbrian Water: Soft to Very hard; Portsmouth Water: no published figure we can read; SES Water: At least hard; Severn Trent Water: Soft to Very hard; South East Water: no published figure we can read; South Staffs Water: Slightly hard to Hard; South West Water: no published figure we can read; Southern Water: no published figure we can read; Thames Water: “all the water in our region is hard” (Thames Water; Thames Water, company-wide); United Utilities: Soft to Hard; Wessex Water: no published figure we can read; Yorkshire Water: Soft to Very hard. Enter your postcode for your own zone's figure.
Sources and method
- DWI england 2025, national compliance ↗ · 2025 · read 13 October 2026
- DWI england 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