Cheshunt Water Hardness & Quality Report (2026)

Cheshunt, in south Hertfordshire on the River Lee in the Lee Valley, is supplied by Affinity Water from the Lee Valley Chalk Aquifer and River Lee storage reservoirs. Affinity Water draws from licensed chalk boreholes in the Hertfordshire Chalk — the Cretaceous Upper Chalk dipslope of the Chiltern Hills draining eastward into the Lee valley — and from the Lee valley reservoir complex. The Chiltern chalk dipslope feeding the Lee valley produces very high dissolved calcium in the chalk groundwater, and the Lee valley reservoirs impound water carrying chalk catchment calcium from the Hertfordshire chalk uplands. Affinity Water treats at the Lee Valley works and distributes to Cheshunt and south Hertfordshire, delivering consistently very hard chalk supply to the Lee valley towns.

Cheshunt's very hard water — 256.5 mg/L (18.0°Clark) — reflects the Hertfordshire Chalk Aquifer and Lee valley reservoir chalk catchment chemistry typical of the south Hertfordshire very hard water zone. The TDS of 667.7 mg/L confirms the high mineral content. The Drinking Water Inspectorate (DWI) classifies this supply as very hard.

Limescale is a very serious household challenge in Cheshunt. At 256.5 mg/L, limescale forms in kettles within one to two weeks requiring fortnightly descaling. Combi-boiler heat exchangers face serious limescale accumulation — annual boiler servicing and a polyphosphate scale inhibitor are essential. Showerheads, taps, and shower screens develop heavy deposits. Washing-up liquid lathers very poorly. Cheshunt homeowners should strongly consider a whole-house water softener for effective protection against the very hard Hertfordshire chalk supply.