Severn Trent Water supplies most of Birmingham (89.8% of its postcodes), and the quality of that water is regulated by the Drinking Water Inspectorate in England and Wales, per ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries (read 26 September 2026).
Source: ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries — read 26 September 2026Contains OS data © Crown copyright and database right 2026Contains Royal Mail data © Royal Mail copyright and database right 2026Source: Office for National Statistics licensed under the Open Government Licence v.3.0Water company boundaries © Water UK, licensed under CC BY 4.0
Drinking Water Inspectorate (DWI) enforces the UK drinking water quality regulations in England and Wales. Figures it classifies or regulates on this page cover England and Wales only.
The official answer
Birmingham is supplied by Severn Trent Water, whose water is regulated by Drinking Water Inspectorate under the UK drinking water quality regulations.
Source: ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries — read 26 September 2026Contains OS data © Crown copyright and database right 2026Contains Royal Mail data © Royal Mail copyright and database right 2026Source: Office for National Statistics licensed under the Open Government Licence v.3.0Water company boundaries © Water UK, licensed under CC BY 4.0
Who supplies Birmingham
Severn Trent Water's supply area (89.8% of the 21,553 live postcodes in Birmingham): 19372 postcodes
Source: ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries — read 26 September 2026Contains OS data © Crown copyright and database right 2026Contains Royal Mail data © Royal Mail copyright and database right 2026Source: Office for National Statistics licensed under the Open Government Licence v.3.0Water company boundaries © Water UK, licensed under CC BY 4.0
South Staffordshire Water's supply area (9.4% of the 21,553 live postcodes in Birmingham): 2030 postcodes
Source: ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries — read 26 September 2026Contains OS data © Crown copyright and database right 2026Contains Royal Mail data © Royal Mail copyright and database right 2026Source: Office for National Statistics licensed under the Open Government Licence v.3.0Water company boundaries © Water UK, licensed under CC BY 4.0
On or near the boundary between South Staffordshire Water and Severn Trent Water (0.6% of the 21,553 live postcodes in Birmingham): 133 postcodes
Source: ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries — read 26 September 2026Contains OS data © Crown copyright and database right 2026Contains Royal Mail data © Royal Mail copyright and database right 2026Source: Office for National Statistics licensed under the Open Government Licence v.3.0Water company boundaries © Water UK, licensed under CC BY 4.0
Not placed in any regional water company's supply area (under 0.1% of the 21,553 live postcodes in Birmingham): 18 postcodes
Source: ONS Postcode Directory (May 2026), each postcode placed in the water companies' supply-area boundaries — read 26 September 2026Contains OS data © Crown copyright and database right 2026Contains Royal Mail data © Royal Mail copyright and database right 2026Source: Office for National Statistics licensed under the Open Government Licence v.3.0Water company boundaries © Water UK, licensed under CC BY 4.0
What Severn Trent Water's own figures show
Severn Trent Water's published drinking water quality results for 2025: 201646 published sample results
Source: Severn Trent Water's published drinking water quality results for 2025, published on the water industry's shared data portal — dated 20 September 2026, read 20 September 2026Severn Trent Water Domestic Water Quality 2025 by Severn Trent Water Limited is licensed under CC BY 4.0
Severn Trent Water's published drinking water quality results for 2023: 195498 published sample results
Source: Severn Trent Water's published drinking water quality results for 2023, published on the water industry's shared data portal — dated 20 September 2026, read 20 September 2026Severn Trent Water Domestic Tap Water Quality 2023 by Severn Trent Water Limited is licensed under CC BY 4.0
Severn Trent Water's published drinking water quality results for 2024: 197727 published sample results
Source: Severn Trent Water's published drinking water quality results for 2024, published on the water industry's shared data portal — dated 20 September 2026, read 20 September 2026Severn Trent Water Domestic Tap Water Quality 2024 by Severn Trent Water Limited is licensed under CC BY 4.0
Severn Trent Water's published drinking water quality results for 2016 to 2018: 830690 published sample results
Source: Severn Trent Water's published drinking water quality results for 2016 to 2018, published on the water industry's shared data portal — dated 20 September 2026, read 20 September 2026Severn Trent Water Domestic Water Quality 2016 - 2020 by Severn Trent Water Limited is licensed under CC BY 4.0
Severn Trent Water's published drinking water quality results for 2021 to 2022: 368579 published sample results
Source: Severn Trent Water's published drinking water quality results for 2021 to 2022, published on the water industry's shared data portal — dated 20 September 2026, read 20 September 2026Severn Trent Water Domestic Water Quality 2021-2022 by Severn Trent Water Limited is licensed under CC BY 4.0
What an independent test shows
We have not tested Birmingham’s water ourselves. Nothing on this page is our own measurement. You can have your own supply tested.
Related pages
- What we hold on tap-water safety, town by town
- Hard water in the UK
- Check your postcode
- Every zone we hold a figure for
- Severn Trent Water: what we hold
- Severn Trent Water hosepipe ban status
- What Severn Trent Water publishes for your postcode
- UK water companies
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- Birmingham, Michigan
- Birmingham, Missouri