Richmond Water Hardness & Quality Report (2026)

Richmond, the prestigious Thames riverside town in the London Borough of Richmond upon Thames — the home of Richmond Park, Kew Gardens and the historic Richmond Green — is supplied by Thames Water predominantly from Hampton Water Treatment Works on the Thames bank, just upstream at Hampton and East Molesey. Hampton WTW abstracts directly from the River Thames, treating the chalk-influenced Thames river water before distribution to the south-west London riverside zone. At 203.5 mg/L with TDS 470.4 mg/L (ratio 2.31), Richmond's supply has a clear Thames surface-water character — lower TDS relative to hardness than chalk borehole-dominant zones, reflecting the Thames river water chemistry rather than the more extreme confined chalk borehole character of outer London. The Thames at Hampton carries chalk-derived calcium bicarbonate from the upper Thames Chiltern, Berkshire Downs and Cotswold limestone catchments at 200–220 mg/L — the characteristic hardness of the middle Thames river corridor at Richmond. Thames Water's Hampton treatment at enormous scale ensures consistent supply to Richmond and the entire south-west London Thames-side zone.

The River Thames at Hampton and Richmond receives chalk-influenced tributary water from the River Mole (Surrey chalk), the River Wey (North Downs chalk) and the River Loddon (Berkshire chalk), maintaining hardness at 195–215 mg/L at this point. Unlike the north and north-east London supply zones where deep confined chalk boreholes drive hardness to 280–320 mg/L, Richmond's Thames surface-water supply tracks the river chemistry more directly, producing a modestly lower and more consistent hardness in the 200–210 mg/L range. The TDS of 470.4 mg/L is characteristic of Thames surface water rather than borehole supply.

At 203.5 mg/L Richmond's water is hard and limescale is a persistent domestic feature. Kettles benefit from monthly descaling with a commercial citric acid tablet. Shower screens develop a calcium film requiring regular white vinegar treatment. Washing-up liquid must be used generously. Combi-boilers benefit from inline scale inhibitor protection. Richmond's exceptional quality of life — the Thames towpath, Richmond Park, the view from the Hill, the Georgian architecture of Richmond Green — is combined with a consistently hard Thames chalk water supply that requires routine limescale management throughout the home.