Chorley Water Hardness & Quality Report (2026)

Chorley, in the Chorley district of Lancashire at the foot of the west Pennines between Preston and Bolton, is supplied by United Utilities from the Rivington Reservoir system — Rivington Upper, Rivington Lower, Yarrow, and Anglezarke — and the Thirlmere Lake District aqueduct. The Rivington reservoirs impound moorland streams from the Carboniferous Millstone Grit of Winter Hill and the west Pennine moors above Chorley, providing soft upland supply. The Thirlmere aqueduct from the Lake District adds very soft Borrowdale Volcanic catchment water, and the south Lancashire supply network blends these. Chorley's position at the foot of the west Pennines in the Rivington supply zone receives the blended upland reservoir supply with only a moderate increment from any groundwater component, producing a moderately soft supply.

Chorley's hardness of 110.5 mg/L (7.8°Clark) reflects the blend of soft Thirlmere Lake District aqueduct and soft Rivington west Pennine Millstone Grit reservoir supply in United Utilities' south Lancashire Chorley distribution zone. The Drinking Water Inspectorate (DWI) classifies this supply as moderately soft.

Limescale is a moderate concern in Chorley. At 110.5 mg/L, limescale forms gradually — kettles need descaling every one to two months. Combi-boiler heat exchangers accumulate modest deposits; annual servicing is sensible. Showerheads and taps develop light deposits. Washing-up liquid lathers reasonably well. A monthly Calgon tablet in the washing machine and a regular kettle descale is adequate limescale management for most Chorley households.