Yorkshire Water Tap Water Quality

Yorkshire Water supplies Yorkshire with drinking water drawn from predominantly upland Pennine reservoirs, with some lowland chalk groundwater in the East Riding.

Yorkshire Water's supply profile reflects the dramatic geography of the region. The vast majority of customers receive soft Pennine reservoir water — Sheffield, Bradford, and Huddersfield typically see hardness below 80 mg/L. The notable exception is Hull and the East Riding, which relies on chalk groundwater and regularly records the hardest water in England at 350–400 mg/L CaCO₃. Iron and manganese levels are periodically elevated in older distribution infrastructure serving urban areas. THM levels in some zones have historically triggered DWI investigation.

Typical water profile

With typical hardness of approximately 90 mg/L CaCO₃, water in the Yorkshire Water supply area is classified as soft to moderately hard. This means minimal limescale risk and good appliance longevity across the supply area.

Notable: Regional split: Pennines very soft, Hull/East Riding extremely hard (~380 mg/L). Hull has among the hardest water in the UK. Active PFAS improvement programme under DWI enforcement.

Is Yorkshire Water water safe to drink?

Yes. All treated water supplied by Yorkshire Water meets the UK Drinking Water Regulations. The Drinking Water Inspectorate (DWI) audits every water company annually — Yorkshire Water serves 5 million customers across 116 supply zones. Each zone is tested thousands of times per year and results are published in the annual compliance report.

However, water quality varies significantly between zones within the Yorkshire Water supply area. Your specific zone may have different hardness, nitrate, or THM levels from your neighbour in a different zone. That's why it's worth checking your exact postcode above.

How to check your Yorkshire Water zone

Enter your postcode in the box above to see zone-specific data for your address — including hardness, nitrates, lead, chlorine, fluoride, and THMs — drawn directly from Yorkshire Water's most recent annual compliance report.