Tewkesbury Water Hardness & Quality Report (2026)

Severn Trent Water supplies Tewkesbury, the historic market town at the confluence of the River Severn and River Avon in Gloucestershire. Water reaching the town is sourced from a blend of the River Severn and groundwater from the Jurassic Limestone aquifer of the Cotswold Hills, treated at Tewkesbury Water Treatment Works and regional facilities. At 231.5 mg/L (16.2°Clark), Tewkesbury's water is hard — notably so for a Severn Valley town, reflecting the considerable influence of Cotswold limestone groundwater on the blended supply.

The Cotswold Hills to the east of Tewkesbury are underlain by Jurassic Oolitic Limestone — thick, porous sequences of calcium carbonate-rich rock forming the Great Oolite and Inferior Oolite formations. Groundwater percolating through these limestones dissolves calcium carbonate extensively, emerging at springs and boreholes with high bicarbonate hardness. The River Avon drains the Cotswolds throughout its upper course, carrying substantial dissolved calcium into Tewkesbury at the confluence with the Severn. This Cotswold limestone contribution substantially elevates hardness above what the River Severn alone — sourced from soft mid-Wales uplands — would produce.

Limescale is a meaningful challenge in Tewkesbury homes. Kettles should be descaled monthly to prevent element degradation and chalky deposits in drinks. The combi-boiler benefits from a fitted scale inhibitor and annual servicing to inspect the heat exchanger for calcium deposits. Washing-up liquid requires slightly more product than in softer-water households to maintain a satisfactory lather. Taps and shower heads accumulate visible limescale within one to two weeks; a fortnightly wipe with white vinegar or a proprietary descaling product is recommended to keep fittings clean and prevent hard-water staining from becoming permanent on surfaces and fixture seals.