Chessington Water Hardness & Quality Report (2026)

Thames Water supplies Chessington in the Royal Borough of Kingston upon Thames, at the southern edge of Greater London bordering Surrey. The town's supply is drawn from the River Thames abstracted at Hampton and treated at Hampton Water Treatment Works, delivered via the Thames Water distribution network across south-west London and into the Kingston borough. At 258 mg/L (18.1°Clark), Chessington's water is in the very hard category, driven by the chalk-influenced Thames source water and the proximity of the North Downs Chalk aquifer underlying the Surrey hinterland.

The North Downs Chalk forms the high ground immediately south of Chessington, and chalk groundwater from the dip slope seeps into the Thames at multiple points, contributing additional dissolved calcium to the river system above Hampton. The Thames itself has traversed the Chiltern Chalk and North Downs catchments upstream, accumulating high calcium bicarbonate throughout its course. The combination of chalk-rich river water and local chalk groundwater inputs makes the supply in the south-west London zone consistently very hard.

Limescale is a serious daily challenge in Chessington. Kettles require descaling fortnightly to prevent element damage and calcium particles in drinks. The combi-boiler requires a fitted scale inhibitor — essential at this hardness level — and annual professional servicing to check the heat exchanger for calcium deposits. Washing-up liquid produces noticeably less lather; more product is needed per wash than in softer areas. Taps, shower heads, and basin mixers develop heavy limescale deposits within a week; regular descaling treatment with white vinegar or a proprietary product is necessary to protect fittings, and a whole-house water softener is strongly recommended for comprehensive long-term protection of appliances and plumbing.