Alton Water Hardness & Quality Report (2026)

South East Water supplies Alton, a market town in north-east Hampshire on the River Wey. The town's water is drawn from deep chalk boreholes penetrating the South Downs and North Hampshire Chalk aquifer, treated at Alresford Water Treatment Works and regional facilities before distribution across the north Hampshire supply zone. The River Wey itself rises at Alton as a classic chalk spring from the Hampshire Chalk, and the town's groundwater supply shares the same geological source. At 189.5 mg/L (13.3°Clark), Alton's water is moderately hard, reflecting the chalk geology that dominates the North Hampshire downland.

The Upper Cretaceous Chalk of the Hampshire Downs forms a broad plateau surrounding Alton to the south and west, with the town situated at the head of the Wey Valley where chalk springs emerge. Groundwater percolating through the chalk dissolves calcium carbonate via the carbonic acid mechanism, emerging with characteristic bicarbonate hardness. The confined chalk beneath the basin of the North Hampshire Chalk aquifer has slightly longer residence times, contributing to the moderate hardness observed in Alton's supply, somewhat below the extremes seen in coastal Hampshire towns closer to the chalk discharge zone.

At 189.5 mg/L, limescale is a visible household concern in Alton. Kettles benefit from descaling every four to six weeks to maintain element efficiency and avoid calcium deposits in hot drinks. The combi-boiler should be fitted with a scale inhibitor and serviced annually to check for heat exchanger deposits. Washing-up liquid performs adequately at normal quantities, though reduced lathering is noticeable. Taps and shower heads develop moderate limescale deposits within a few weeks; a fortnightly wipe with white vinegar or a proprietary descaling solution keeps fittings clean and prevents hard-water staining from becoming established on surfaces and seals.