West Wickham Water Hardness & Quality Report (2026)

South East Water supplies West Wickham, a suburban area in the London Borough of Bromley at the southern edge of Greater London adjoining the North Downs chalk hills near Keston and Addington, from North Downs Chalk boreholes in the Bromley–Croydon supply zone, treated at regional south London chalk works. At 215.5 mg/L (15.1°Clark), West Wickham's water is hard — somewhat softer than the very hard supply at nearby Chelsfield (273.5 mg/L) and Shirley (276 mg/L) — reflecting the particular chalk borehole blend in the West Wickham distribution sub-zone of the South East Water Bromley network.

West Wickham sits at the northernmost edge of the North Downs chalk plateau, where the Upper Chalk dips northward beneath the London Clay. The South East Water North Downs supply zone at West Wickham draws on chalk boreholes at a position where the chalk aquifer is beginning its northward dip under Tertiary cover, producing chalk-influenced water at 215.5 mg/L with TDS 498.5 mg/L — somewhat less mineralised than the fully exposed chalk outcrop zones further south and east on the North Downs. The relatively low TDS/hardness ratio is consistent with a typical chalk-derived bicarbonate hardness supply.

At 215.5 mg/L, limescale is a consistent household concern in West Wickham. Kettles should be descaled monthly. The combi-boiler benefits from a fitted scale inhibitor and annual professional servicing. Washing-up liquid requires more product than in softer areas. Taps and shower heads develop visible white limescale deposits within one to two weeks; a fortnightly wipe with white vinegar or a proprietary descaling product keeps fittings clean and prevents staining from building up on surfaces in this hard North Downs chalk-supplied south London community.