Havant Water Hardness & Quality Report (2026)

Havant, in the Borough of Havant in south Hampshire on the coastal plain between Portsmouth and Chichester, is supplied by Portsmouth Water from the South Downs Chalk Aquifer. Portsmouth Water operates licensed chalk borehole abstractions at Farlington and the east Hampshire chalk dip slope — the Cretaceous Upper Chalk that forms the South Downs behind Havant — and distributes chalk groundwater to Havant and the east Portsmouth/Havant coastal area. The chalk here is the same Portsdown Hill and east Hampshire chalk formation serving Waterlooville (219.5 mg/L) and Gosport (254.5 mg/L) on the Portsmouth Water supply network. Havant's slightly lower hardness compared to Waterlooville reflects its more coastal position further from the main chalk recharge zone, with greater network dilution.

Havant's hard water — 206 mg/L (14.5°Clark) — reflects the South Downs Chalk Aquifer supply via Portsmouth Water's east Hampshire chalk borehole network. The chalk of the South Downs behind Havant contributes high dissolved calcium consistent with the hard Hampshire chalk supply zone. The Drinking Water Inspectorate (DWI) classifies this supply as hard.

Limescale is a persistent household challenge in Havant. At 206 mg/L, limescale forms in kettles within two to three weeks and monthly descaling is advisable. Combi-boiler heat exchangers accumulate deposits steadily — annual boiler servicing and an in-line scale inhibitor are recommended. Showerheads, taps, and shower screens develop regular deposits. Washing-up liquid lathers poorly. Using Calgon monthly in the washing machine and maintaining a regular descaling routine is important limescale management for Havant households on the Portsmouth Water chalk supply.