Witney Water Hardness & Quality Report (2026)

Thames Water serves Witney and nearby areas in Oxfordshire, drawing its supply from a blend of surface waters, including the River Thames and Evenlode, alongside groundwater tapped from the Cotswold limestone aquifer. The water undergoes processing at regional treatment plants before reaching local homes and businesses.

The Witney water originates from the Cotswolds' Jurassic limestone bedrock, specifically the Inferior Oolite and Great Oolite formations. These extensive limestone aquifers, along with the rivers that traverse them, naturally absorb substantial amounts of calcium and magnesium. This geological setting, particularly within the Thames catchment, imbues the water with a high mineral content, leading to the characteristically hard water found throughout the South East.

Residents in this hard water area will notice limescale deposits forming on common household items like kettles and shower heads, and may find that soaps and detergents don't lather as effectively. Appliances such as dishwashers, washing machines, and especially water heaters can suffer from scale buildup, impacting their efficiency and longevity. Many homeowners opt for installing water softeners to combat these issues. Thames Water ensures the water meets stringent UK drinking standards through processes like coagulation, sedimentation, filtration, and chlorination.