Selsey Water Hardness & Quality Report (2026)

Selsey in West Sussex gets its water from Southern Water Services Ltd. The supply primarily comes from groundwater drawn from boreholes within the South Downs Chalk aquifer, a key source in the Southeast England Basin. Water is treated at facilities such as Ham Farm or Tangmere works. Here, it undergoes filtration, disinfection using chlorine, and fluoridation before being sent to customers across Kent, Sussex, Hampshire, and the Isle of Wight. Southern Water also manages reservoirs and interconnectors, but groundwater from the local aquifer is crucial for this coastal community. The watershed covers the Arun and coastal catchments, feeding into the Chalk Group aquifer beneath the South Downs National Park.

The geology here is defined by the Upper Chalk Group, a thick formation of fractured Cretaceous limestone. This porous rock allows rainwater to infiltrate, dissolving significant amounts of calcium carbonate. The karstic features and fissures within this chalky bedrock, particularly in the Hampshire Sussex Downs, accelerate mineral leaching. This natural process imbues the groundwater with a high mineral content, characteristic of the region's calcareous geology and resulting in a very hard water supply. The subsurface flow through these limestone strata over millennia has shaped its mineralised profile, with minimal surface influences. This is typical for Southeast England's oolitic and calcareous bedrock.

This very hard water means you'll likely see limescale buildup in appliances like kettles, boilers, and washing machines, which can reduce their efficiency and lifespan. You might notice white deposits, clogged pipes, or scum on fixtures, potentially increasing energy costs. To combat this, homeowners often descale appliances with vinegar or citric acid, or consider installing magnetic conditioners. For persistent issues like staining on glassware or dry skin from soap scum, fitting an ion-exchange water softener is highly recommended to mitigate damage and improve daily life. The water quality here meets UK standards, with a typical pH between 7.2-7.6, and Southern Water provides detailed reports.