Tynemouth Water Hardness & Quality Report (2026)

Tynemouth, the coastal town in North Tyneside at the north bank of the Tyne estuary, is supplied by Northumbrian Water from the River Tyne catchment and the Kielder Transfer Scheme. The Tyne supply at Tynemouth blends Kielder Water (from the North Tyne in Northumberland) and upper South Tyne contributions, treated at Horsley Water Treatment Works in Northumberland. Tynemouth's coastal position on the Magnesian Limestone plateau of north Tyneside — the seaward extension of the Permian limestone escarpment of County Durham and Northumberland — gives the local water a moderate limestone groundwater influence compared to purely Tyne-fed inland supply zones. Northumbrian Water's distribution blend serving north Tyneside incorporates a proportion of Magnesian Limestone groundwater from the coastal limestone aquifer.

Tynemouth's hardness of 151 mg/L (10.6°Clark) reflects the blend of soft Kielder and Tyne supply with a moderate Permian Magnesian Limestone groundwater contribution. The Magnesian Limestone plateau at Tynemouth is the same Permian dolomitic limestone escarpment that runs south through east Durham — a productive limestone aquifer yielding moderately hard, calcium and magnesium-rich water. The blend diluted by the very soft Kielder supply produces a moderately hard result. The Drinking Water Inspectorate (DWI) classifies this supply as moderately hard.

Limescale is a moderate household concern in Tynemouth. At 151 mg/L, limescale forms gradually in kettles and descaling every one to two months is typically sufficient. Combi-boiler heat exchangers accumulate modest deposits; annual servicing is sensible. Showerheads and taps develop light deposits. Washing-up liquid lathers reasonably well. Adding Calgon monthly to the washing machine and a regular kettle descale provides adequate limescale management for most Tynemouth households on the north Tyneside supply.