Eastbourne Water Hardness & Quality Report (2026)

Eastbourne, the coastal resort in East Sussex at the foot of the South Downs, is supplied by South East Water drawing from the South Downs Chalk Aquifer — one of the most significant groundwater resources in southern England. South East Water operates licensed boreholes in the South Downs chalk east of Eastbourne and to the north in the downland above Polegate, sinking into the thick Cretaceous Upper Chalk that forms the South Downs. Beachy Head, immediately south-west of Eastbourne, is a 162-metre chalk headland that exemplifies the South Downs chalk escarpment — the same geological formation accessed by South East Water's Eastbourne boreholes. Chalk groundwater draining toward the coastal plain carries high dissolved calcium by the time it reaches abstraction depth. Water is treated at South East Water's East Sussex facilities before distribution to Eastbourne.

Eastbourne's very hard water — 278.5 mg/L (19.5°Clark) — is a direct product of the South Downs Chalk Aquifer. The chalk of the South Downs is a thick sequence of Cretaceous Upper Chalk (Turonian and Santonian stage) — essentially pure calcium carbonate deposited in a shallow tropical sea approximately 75–90 million years ago. Groundwater percolating through this chalk over years or decades dissolves very high quantities of calcium carbonate. The South Downs chalk aquifer is particularly productive in the Eastbourne and Lewes area, giving Eastbourne and the surrounding coastal strip some of the hardest water in East Sussex. The Drinking Water Inspectorate (DWI) classifies this supply as very hard.

Limescale is a serious and persistent challenge in Eastbourne homes. At 278.5 mg/L, limescale forms rapidly in kettles — a white crust within one to two weeks requiring fortnightly descaling. Combi-boiler heat exchangers accumulate serious limescale deposits; annual boiler servicing with limescale inspection is essential, and fitting an in-line polyphosphate scale inhibitor is strongly recommended. Showerheads, taps, and glass shower screens develop heavy limescale deposits requiring regular aggressive removal. Washing-up liquid lathers poorly. Eastbourne homeowners — particularly in the town's considerable retired and seaside property market — should prioritise limescale management across all household appliances.