Corsham Water Hardness & Quality Report (2026)

Bristol Water supplies Corsham, a handsome market town in north Wiltshire famous for Corsham Court, its historic stone quarrying industry, and the Bath Stone (Great Oolite) that underlies the town — near the Wiltshire–Avon border in the northern Wiltshire limestone plateau country — from Cheddar Reservoir in the Mendip Hills and Cotswold Jurassic Limestone spring and borehole supply, treated at Barrow Water Treatment Works near Barrow Gurney south of Bristol. At 147.5 mg/L (10.3°Clark), Corsham's water is moderately hard, consistent with the calcareous Jurassic Oolitic Limestone (Bath Stone/Great Oolite) geology that defines the north Wiltshire and Cotswold fringe water character.

Corsham sits on the Great Oolite limestone formation — the famous Bath Stone quarried locally since Roman times — that dips gently northward from the Cotswolds into the north Wiltshire plateau. Bristol Water draws on the Jurassic limestone spring supply from the Cotswold fringe to supplement the Cheddar Reservoir surface supply, yielding moderately hard calcium bicarbonate groundwater characteristic of the oolite limestone aquifer. The resulting 147.5 mg/L with TDS 342.2 mg/L is a pleasant, moderately hard supply reflecting the celebrated Bath Stone geology beneath Corsham's own streets.

At 147.5 mg/L, limescale is a noticeable household concern in Corsham. Kettles benefit from descaling every four to six weeks. The combi-boiler should be fitted with a scale inhibitor and serviced annually. Washing-up liquid requires slightly more product than in softer areas. Taps and shower heads develop moderate limescale deposits within two to three weeks; a monthly wipe with white vinegar keeps fixtures in good condition. The moderately hard Jurassic limestone supply is a fitting quality for a town built almost entirely on and from the Great Oolite limestone that defines north Wiltshire's unique stone-built townscape.