Ely Water Hardness & Quality Report (2026)

Anglian Water supplies Ely, the cathedral city in Cambridgeshire, from a combination of groundwater from the Chalk aquifer of the East Anglian uplands and surface water from the River Great Ouse catchment, treated at Ely and Isleham water treatment works. Ely stands on an island of Greensand and clay rising above the surrounding Fenland, but its water supply draws heavily on the chalk aquifer to the east and south of the city. At 210.5 mg/L (14.8°Clark), Ely's water is firmly in the hard category, consistent with the chalk-dominated hydrogeology of inland Cambridgeshire.

The Upper Cretaceous Chalk of Cambridgeshire forms a broad upland plateau to the east of Ely and dips westward beneath the Fens, where it becomes confined beneath Cretaceous and Quaternary clays. Groundwater abstracted from boreholes in the chalk has percolated through porous rock for long periods, dissolving calcium carbonate extensively via the carbonic acid mechanism. The River Great Ouse also contributes surface water with significant chalk-derived hardness, having drained chalk catchments from Northamptonshire and Bedfordshire through its upper course.

Limescale is a persistent household concern in Ely. Kettles should be descaled monthly to maintain efficiency and prevent chalky particles in drinks. The combi-boiler benefits from a fitted scale inhibitor to protect the heat exchanger from calcium carbonate build-up, and annual servicing is recommended. Washing-up liquid requires slightly more product than the manufacturer suggests to achieve a good lather. Taps and shower heads develop visible white limescale deposits within one to two weeks; a fortnightly treatment with white vinegar or a proprietary descaler keeps fittings clean and prevents hard-water staining from becoming permanent across surfaces and seals.