Amersham on the Hill Water Hardness & Quality Report (2026)

Affinity Water supplies Amersham on the Hill in Buckinghamshire, a commuter town on the Metropolitan Line in the Chiltern Hills. Supply is drawn from deep boreholes in the Chiltern Chalk aquifer in the Chess Valley and Misbourne Valley east of Amersham, treated at regional Chilterns works before distribution across the Chiltern supply zone. At 195.5 mg/L (13.7°Clark), Amersham on the Hill's water is moderately hard, reflecting the classic calcium bicarbonate character of the Chiltern Chalk groundwater that defines the Affinity Water supply zone in this part of Buckinghamshire and Hertfordshire.

The Chiltern Hills are underlain by Upper Cretaceous Chalk — a highly porous, permeable aquifer extending north-eastward from the Berkshire–Hampshire border across Buckinghamshire and Hertfordshire. Deep boreholes in the Misbourne Valley and Chess Valley below Amersham access chalk groundwater that has infiltrated from the high Chiltern plateau and percolated through hundreds of metres of pure chalk, dissolving calcium carbonate to produce the characteristic calcium bicarbonate hardness of the region. The Chiltern Chalk aquifer is one of the most important groundwater resources in south-east England.

At 195.5 mg/L, limescale is a noticeable domestic concern in Amersham on the Hill. Kettles benefit from descaling every four to six weeks to maintain efficiency. The combi-boiler should be fitted with a scale inhibitor and serviced annually. Washing-up liquid requires slightly more product than in softer areas to achieve a satisfactory lather. Taps and shower heads develop visible white limescale deposits within one to two weeks; a fortnightly wipe with white vinegar or a proprietary descaling solution keeps fittings clean and prevents hard-water staining from building up permanently on surfaces throughout this picturesque Chiltern town.