Southsea Water Hardness & Quality Report (2026)

Portsmouth Water supplies Southsea, a seaside suburb of Portsmouth on Portsea Island, from the Havant and Bedhampton chalk springs — one of the most productive natural chalk spring systems in England — treated at Bedhampton Water Treatment Works before distribution across Portsmouth and the surrounding area. At 221.5 mg/L (15.5°Clark), Southsea's water is hard, reflecting the chalk groundwater that is the defining characteristic of Portsmouth Water's supply — a company unusual in drawing almost entirely on a single chalk spring complex.

The Havant and Bedhampton springs emerge at the foot of the South Downs where confined chalk aquifer water reaches the spring line. The Upper Cretaceous Chalk of the South Downs has been recharged over thousands of years, and groundwater percolates through hundreds of metres of porous limestone, dissolving calcium carbonate throughout its long underground transit. The spring water arrives at Bedhampton highly mineralised with calcium bicarbonate — characteristic of deep, slowly circulating chalk aquifer water — and this hardness character is retained through treatment and distribution to the Portsea Island communities.

Limescale is a consistent daily concern in Southsea. Kettles should be descaled monthly to maintain efficiency and prevent chalky deposits in drinks. The combi-boiler benefits from a fitted scale inhibitor to protect the heat exchanger from calcium carbonate build-up, and annual servicing is advisable. Washing-up liquid requires slightly more product than in softer areas to achieve a good lather. Taps and shower heads develop visible white limescale deposits within one to two weeks; a fortnightly wipe with white vinegar or a proprietary descaling solution keeps fittings clean and prevents hard-water staining from becoming a permanent fixture of the bathroom and kitchen.