Saint Ives Water Hardness & Quality Report (2026)

Anglian Water supplies Saint Ives, a market town on the Great Ouse in the Cambridgeshire Fen edge, from the East Anglian Chalk aquifer and from surface water abstraction on the River Great Ouse and River Cam catchments, treated at Hinxton and regional Cambridgeshire works before distribution. At 293 mg/L (20.6°Clark) and a TDS of 855.9 mg/L, Saint Ives's water is very hard — driven by the deeply saturated chalk aquifer that underlies the Cambridgeshire Fen edge and the chalk-dominated rivers of the Ouse Valley.

The East Anglian Chalk forms a broad, gently dipping plateau south and south-east of Saint Ives, where groundwater has been accumulating dissolved calcium carbonate over extended residence times in the confined aquifer beneath the Fens. The River Great Ouse and River Cam drain chalk catchments over their entire upper courses, arriving at the Fen edge heavily mineralised with calcium bicarbonate. Together, these chalk-dominated sources produce the very hard water of the Cambridgeshire Fen edge — with TDS approaching 900 mg/L — that characterises Anglian Water's supply zone across the south and east Cambridgeshire basin.

Limescale is a significant and persistent challenge in Saint Ives. Kettles require descaling fortnightly to prevent element damage and calcium deposits. The combi-boiler needs a properly fitted scale inhibitor and annual professional servicing to guard against heat exchanger damage from the sustained chalk calcium load. Washing-up liquid produces reduced lather; more product is needed per wash. Taps, shower heads, and basin mixers develop heavy limescale deposits within a week or two; a fortnightly descaling wipe with white vinegar or a proprietary product is advisable. A whole-house water softener is strongly recommended to protect all appliances and plumbing from relentless limescale accumulation.