Kenley Water Hardness & Quality Report (2026)

South East Water supplies Kenley, a residential area of the London Borough of Croydon set on and around the North Downs chalk plateau at Kenley Aerodrome, from the North Downs Chalk aquifer at the Surrey–Croydon plateau margin, treated at regional north Surrey and Kent chalk works. At 283.5 mg/L (19.9°Clark) and a TDS of 767 mg/L, Kenley's water is very hard — driven by the North Downs Chalk that lies at or near the surface beneath Kenley and the adjacent chalk plateau between Caterham and Coulsdon.

Kenley sits directly on the Upper Chalk plateau of the North Downs, where the chalk is exposed at Kenley Aerodrome and in the dry valleys around Old Coulsdon. This is one of the few places within Greater London where the chalk is not deeply buried by London Clay or Thanet Sand — the chalk aquifer is active and close to the surface, absorbing rainfall directly and producing hard, calcium-saturated groundwater within very short residence times. South East Water's supply in the Kenley and Caterham zone draws heavily on this shallow, active chalk, producing 283.5 mg/L hardness with TDS 767 mg/L that rivals the hardest chalk supply zones in Kent.

At 283.5 mg/L, limescale is a significant and persistent household challenge in Kenley. Kettles require descaling fortnightly to prevent rapid element damage. The combi-boiler needs a properly fitted scale inhibitor and annual professional servicing. Washing-up liquid requires considerably more product per wash. Taps, shower heads, and basin mixers develop heavy chalk deposits within one to two weeks; a fortnightly descaling wipe with white vinegar or a proprietary product is essential to keep fittings clean. A whole-house water softener is strongly recommended for all Kenley households to protect appliances and plumbing from this very hard North Downs chalk supply.