Rustington Water Hardness & Quality Report (2026)

Southern Water supplies Rustington, a coastal village near Littlehampton in West Sussex — a pleasant seaside residential community between Littlehampton and Worthing on the Sussex coastal plain — from South Downs Chalk boreholes in the coastal West Sussex supply zone, treated at Hardham Water Treatment Works near Pulborough. At 327.5 mg/L (23.0°Clark) and a TDS of 972.4 mg/L, Rustington's water is extremely hard — among the very hardest public supplies in England, matching Forest Hill (327 mg/L) and rivalling Broxbourne (324.5 mg/L), Ashtead (321 mg/L), and Ladywell (316.5 mg/L) in the top tier of British extreme hard water zones.

Rustington sits on the West Sussex Coastal Plain between the South Downs chalk escarpment and the sea — a thin strip of Quaternary sediments above which the highly productive South Downs Upper Chalk aquifer is recharged from the Downs crest. Southern Water draws on South Downs chalk boreholes throughout West Sussex, delivering chalk-saturated groundwater with 327.5 mg/L and TDS 972.4 mg/L to the coastal plain communities. The South Downs chalk aquifer in West Sussex is one of the most mineralised in Britain, consistently producing water in the 300–350 mg/L hardness range from Chichester to Worthing.

At 327.5 mg/L, limescale is an extreme and relentless household problem in Rustington. Kettles must be descaled weekly to prevent rapid element failure. The combi-boiler faces very high risk of premature breakdown without a properly fitted, annually replaced scale inhibitor and regular professional servicing. Washing-up liquid requires very generous quantities of product for any lather. Taps, shower heads, and basin fittings develop heavy chalk encrustation within days; at minimum a weekly descaling with white vinegar or a proprietary product is essential. A whole-house water softener is very strongly recommended for all Rustington households to protect appliances from this extreme South Downs chalk supply.