About TapWater.uk
TapWater.uk is an independent water quality research project. We aggregate data from UK government sources to provide free, postcode-searchable water quality reports for every area in England and Wales.
Areas covered
Water tests
PFAS alerts
Updates
Our data sources
Environment Agency
Water Quality Archive — environmental monitoring of rivers, groundwater, and source waters across England
Drinking Water Inspectorate
DWI compliance data — the regulator responsible for drinking water quality in England and Wales
Stream Water Data Portal
Real tap water test results direct from UK water companies — the most granular source available
All data is published under the Open Government Licence v3
Who we are
TapWater.uk is an independent research project by CCC Impact BV, focused on making public environmental data accessible to normal people. The project grew from a simple question: what's actually in my tap water, and why is it so hard to find out?
We aggregate data from the Stream Water Data Portal (real drinking water test results from UK water companies), the Environment Agency Water Quality Archive, and the ONS postcode database. Every score is computed transparently using our published methodology — no black boxes, no hidden algorithms.
This is not a water filter company. We don't sell filters, we don't take money from water companies, and we don't run ads. The data speaks for itself.
Our Mission
Water quality data in the UK is public, but it is scattered across multiple government portals, presented in technical formats, and difficult for ordinary households to interpret. Our mission is to change that. We believe everyone should be able to type in their postcode and immediately understand what is in their tap water — without needing a science degree or hours of research.
By bringing together data from the Drinking Water Inspectorate, individual water companies, and the Environment Agency, we provide a single, plain-English view of water quality that is updated regularly and completely free to use.
How It Works
Our reports are built from three complementary data layers:
- Drinking Water Inspectorate (DWI) — the primary source of treated tap water quality data, covering 48 regulated parameters tested at the tap across England and Wales.
- Water company data — postcode-level supply zone information from the approximately 20 licensed water companies, giving us the most granular geographic mapping available.
- Environment Agency monitoring — supplementary environmental water quality data covering rivers, groundwater, and source waters, which provides broader ecological context for your local area.
You can read more about how we combine these sources on our data sources page, and how we calculate quality scores on our methodology page.
What We Are Not
TapWater.uk is an independent research project. We are not affiliated with any water company, government body, or regulator. Nothing on this site constitutes medical or health advice. Our scores and reports are intended to help you understand publicly available data, not to replace professional guidance.
If you have specific concerns about your water supply — such as a discolouration, unusual taste, or odour — please contact your water supplier directly. They are the authoritative source for supply issues and can carry out testing at your property.
Contact
For questions, corrections, or data feedback, email us at hello@tapwater.uk.