Littlehampton Water Hardness & Quality Report (2026)

Littlehampton, the coastal town in West Sussex at the mouth of the River Arun, is supplied by Southern Water from the South Downs Chalk Aquifer and the River Arun catchment. Southern Water abstracts from chalk boreholes on the South Downs escarpment north and north-east of Littlehampton — accessing the Cretaceous Upper Chalk that forms the South Downs plateau — and blends this with River Arun surface water catchment supply. The Arun catchment drains both chalk country (the South Downs between Arundel and Storrington) and the Weald (the Greensand and Gault Clay country north of the Downs), producing a more moderate hardness than the pure chalk borehole supply. Water is treated at Southern Water's west Sussex facilities before coastal distribution.

Littlehampton's hardness of 197 mg/L (13.8°Clark) reflects the South Downs Chalk Aquifer supply blended with the softer River Arun Weald catchment contributions. The chalk of the South Downs yields hard groundwater from the Cretaceous Upper Chalk, but the Arun's Wealden surface water dilutes the chalk component, producing moderate hardness characteristic of Southern Water's west Sussex coastal zone. The Drinking Water Inspectorate (DWI) classifies this supply as moderately hard.

Limescale is a regular household concern in Littlehampton. At 197 mg/L, limescale forms in kettles within three to four weeks and monthly descaling is advisable. Combi-boiler heat exchangers accumulate deposits; annual servicing with a limescale check and an in-line scale inhibitor are recommended. Showerheads, taps, and bath surfaces develop consistent deposits. Washing-up liquid lathers moderately. Using Calgon monthly in the washing machine and maintaining a regular descaling routine is standard limescale management for Littlehampton households.