Worthing Water Hardness & Quality Report (2026)

Worthing, the coastal town in West Sussex, is supplied by Southern Water drawing from the South Downs Chalk Aquifer — one of the most significant chalk groundwater resources in southern England. The South Downs rise immediately north of Worthing, and Southern Water operates a network of licensed boreholes sinking into the chalk at sites along the downs, including the Worthing and Lancing borehole fields and the Pulborough abstraction area. The chalk aquifer beneath the South Downs is recharged by rainfall on the chalk escarpment, and groundwater migrates southward through the chalk toward the coastal coastal plain where Worthing sits. This chalk groundwater carries very high dissolved calcium concentrations by the time it reaches coastal abstraction boreholes. Water is treated at Southern Water's Hardham Water Treatment Works and other Sussex sites before distribution to the coastal strip.

Worthing's very hard water — 318 mg/L (22.3°Clark) — is a direct product of the South Downs Chalk Aquifer. The chalk of the South Downs is a thick sequence of Cretaceous Upper and Middle Chalk — essentially pure calcium carbonate — that extends from the chalk cliffs of the Seven Sisters and Beachy Head westward to Hampshire. Groundwater migrating through this chalk over years or decades acquires very high dissolved calcium concentrations. The South Downs chalk aquifer is among the most productive and calcium-rich chalk systems in England, giving the coastal Sussex towns some of the hardest water in the country. The Drinking Water Inspectorate (DWI) classifies this supply as very hard.

Limescale is an extreme and persistent challenge in Worthing. At 318 mg/L, limescale accumulates rapidly — a white crust forms in kettles within days to one week, requiring weekly or fortnightly descaling. Combi-boiler heat exchangers face serious rapid limescale accumulation; annual servicing with limescale inspection is essential and fitting a polyphosphate scale inhibitor is strongly recommended. Showerheads block with deposits within weeks, and glass shower screens develop stubborn limescale that requires regular aggressive treatment. Washing-up liquid lathers very poorly. Worthing homeowners should strongly consider a full water softener for comprehensive limescale management across all household appliances and surfaces.