Cranleigh Water Hardness & Quality Report (2026)

South East Water provides the drinking water for Cranleigh and surrounding parts of Surrey, UK. The supply is drawn entirely from groundwater, specifically from local chalk aquifers tapped by boreholes. These sources are managed within the South East Water region, which covers parts of Kent and Sussex as well. Treatment facilities in the area are designed to handle the naturally hard groundwater characteristic of this chalk geology. The overall watershed includes the South Downs and Wealden areas, where the underlying rock formations play a significant role in the water's composition.

The water's journey begins in the Upper Cretaceous Chalk Group, a porous limestone formation found across southern England. As rainwater filters through the fissured chalk, it dissolves substantial amounts of calcium and magnesium minerals. This prolonged interaction between water and rock, particularly within the karstic nature of the chalk aquifers in the Wealden anticline and surrounding structures, gives the groundwater its consistently hard character. Unlike surface water sources, this aquifer-fed supply is rich in dissolved minerals due to the confined, subsurface environment.

Homeowners in Cranleigh will notice the effects of this very hard water, primarily through limescale buildup. Kettles, boilers, showerheads, and washing machines are prone to developing scale, which reduces their efficiency and shortens their lifespan. You might also see scum formation on taps and fixtures, especially around hot water systems and appliances. To combat this, regular descaling with vinegar or citric acid, cleaning filters, and keeping boiler temperatures below 60°C are helpful measures. Installing a water softener is strongly recommended to prevent scaling and protect your household appliances. South East Water ensures the water meets all UK drinking standards, with standard treatment processes like filtration and disinfection applied.