East Molesey Water Hardness & Quality Report (2026)

Thames Water supplies East Molesey in Surrey, a riverside town on the south bank of the Thames adjacent to Hampton Court Palace. The supply is drawn from the River Thames abstracted at Hampton and processed at Hampton Water Treatment Works, distributed across the eastern Elmbridge area of Surrey. At 240.5 mg/L (16.9°Clark), East Molesey's water is in the hard category — harder than its neighbour West Molesey — reflecting the specific distribution zone blending proportions and the proximity of chalk groundwater inputs from the North Downs.

The North Downs Chalk aquifer underlies the Surrey hills immediately south of East Molesey, and chalk groundwater seeps northward into the Thames between Walton and Hampton, enriching the river with dissolved calcium. Hampton Water Treatment Works treats the Thames abstraction but retains the naturally occurring dissolved calcium hardness. East Molesey's distribution zone may draw more heavily on the chalk-influenced Thames water abstracted close to the natural chalk spring lines, explaining the somewhat higher hardness compared to West Molesey from the same general treatment complex.

Limescale is a persistent domestic concern in East Molesey. Kettles should be descaled monthly, with fortnightly descaling worthwhile for frequent users, to prevent element damage and calcium particles in drinks. The combi-boiler benefits from a fitted scale inhibitor and annual servicing. Washing-up liquid requires more product than in softer-water areas to achieve a good lather. Taps and shower heads develop visible limescale within a week or two; a fortnightly wipe with white vinegar or a proprietary descaler prevents hard-water staining from becoming permanent on fittings, joint faces, and seals in this consistently hard Thames Valley supply.