Readings shown come from laboratory results published by UK water companies. Always verify current readings with your water supplier before making health decisions.
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About Water Directory

Coming soon

We're expanding this page with full data source details and who built it. Check your postcode below in the meantime.

Where the data comes from

Chemical readings — nitrates, lead, chlorine, fluoride, hardness — are from water companies' published lab results: most via the Stream open data initiative, and Thames Water's from its EIR release (EIR-26-27-582). We are independent and not affiliated with any water company.

How the postcode lookup works

We use postcodes.io to map your postcode to a supply zone (LSOA). Each zone has lab results from your water supplier. For Northern Ireland we use Open Data NI. Sewage spill data is from the Environment Agency EDM dataset (England and Wales only).

Data sources

  • Stream / streamwaterdata.co.uk — water company chemical data
  • Thames Water EIR release (EIR-26-27-582) — Thames Water chemical data
  • postcodes.io — postcode to LSOA lookup
  • Environment Agency EDM — sewage spill data
Look up your postcode →