Downham Market Water Hardness & Quality Report (2026)

Anglian Water supplies Downham Market, the west Norfolk market town on the Fen Edge — a lively Fenland market town at the boundary of the peat fen and the chalk upland, with a distinctive pink clock tower, the adjacent Denver Sluice (the great Fen drainage control structure), and a setting in the broad Norfolk fenland landscape of open skies and the River Great Ouse at the fen edge — from the Norfolk Chalk (Cretaceous) aquifer boreholes in the west Norfolk Fenland supply zone, treated at Whitlingham Water Treatment Works near Norwich. At 263.5 mg/L (18.5°Clark) and a TDS of 716.9 mg/L, Downham Market's water is very hard — consistent with the productive Cretaceous Chalk aquifer of west Norfolk that delivers persistently very hard, mineralised groundwater characteristic of the Anglian Water Norfolk distribution zone.

Downham Market lies at the Fen Edge where the chalk upland meets the Fens. Anglian Water draws from Norfolk Chalk boreholes beneath the Fenland at the chalk margin, with the Upper Chalk aquifer delivering calcium carbonate groundwater enriched by sulphate from the Upper Greensand beneath the chalk, producing 263.5 mg/L with TDS 716.9 mg/L — very hard water with an elevated TDS/hardness ratio (2.72) consistent with chalk groundwater with moderate Greensand sulphate contribution characteristic of the west Norfolk Fenland chalk supply zone at King's Lynn (265 mg/L) and Wisbech (272 mg/L).

At 263.5 mg/L, limescale is a persistent and significant household problem in Downham Market. Kettles should be descaled every two to three weeks. The combi-boiler needs a fitted scale inhibitor and annual professional servicing. Washing-up liquid requires generous quantities for adequate lather. Taps and shower heads develop substantial white chalk deposits within a week to ten days; a fortnightly descaling with white vinegar or a proprietary product keeps fittings in good condition. Downham Market's very hard chalk supply is characteristic of the Norfolk Fen Edge — the same chalk ridge that holds back the peat fens also delivers highly mineralised chalk groundwater to every home in the town.