Epsom Water Hardness & Quality Report (2026)

Epsom, the North Downs market town in Surrey renowned for its famous racecourse and the historical discovery of Epsom salts, is served by South East Water. Supply comes from deep boreholes sunk into the North Downs Chalk Aquifer directly beneath and to the south of the town, where the chalk dip slope of the North Downs creates a substantial saturated chalk horizon. Water is treated at Horton Water Treatment Works near Epsom and distributed through South East Water's central Surrey network. The chalk here lies close to the surface at Epsom Downs, historically the source of natural springs rich in magnesium sulphate — the original Epsom salts — and continues to produce hard, mineral-rich water for the town today.

The Cretaceous White Chalk of the North Downs dip slope is a thick, highly permeable aquifer with long groundwater residence times. As rainwater percolates downward through the chalk mass above Epsom, it dissolves calcium and bicarbonate ions to reach concentrations of 200–230 mg/L in the unconfined aquifer beneath the town. The proximity to the North Downs escarpment and the presence of the Epsom Downs chalk spur mean that a substantial unsaturated zone allows extended mineral acquisition before groundwater reaches the water table, contributing to the town's characteristic hard-water supply. The hardness here closely resembles that of nearby Ewell, reflecting the same contiguous chalk aquifer.

At 222 mg/L Epsom's water is hard and limescale is a persistent household challenge. Kettle elements require monthly descaling with white vinegar or a citric acid kettle descaler. Shower heads and tap nozzles need regular soaking to prevent blocked jets from accumulated limescale. Washing-up liquid produces less lather than in soft-water areas, so a liberal amount is needed for clean results. An inline magnetic scale conditioner fitted before combi-boilers and washing machines will help reduce internal scaling. Residents who manage a raceyard or horse stabling — common in the Epsom area — will also notice limescale accumulation in water troughs and supply pipes.