Melksham Water Hardness & Quality Report (2026)

Wessex Water supplies Melksham, a market town in north Wiltshire, from a combination of surface water abstracted from the River Avon and groundwater from the Jurassic Limestone and Chalk aquifers of the Wiltshire downland, treated at Hannington Water Treatment Works before distribution across north Wiltshire. At 194 mg/L (13.6°Clark), Melksham's water is moderately hard — a level consistent with the limestone-influenced geology of this part of Wiltshire, where the Jurassic formations of the Cotswold fringe contribute dissolved calcium to both the river and groundwater supply.

Melksham sits within the Vale of Pewsey geological zone, where Jurassic Clay and Triassic formations underlie the low ground, but the surrounding hills expose Great Oolite and Inferior Oolite Jurassic limestones that are significant aquifers in north Wiltshire. The River Avon drains both limestone Cotswold uplands and the chalk downlands of Wiltshire, accumulating calcium bicarbonate from limestone dissolution throughout its catchment. This oolite and chalk influence sustains moderate hardness in the Melksham supply zone across seasonal variations.

At 194 mg/L, limescale is a noticeable but manageable domestic concern in Melksham. Kettles benefit from descaling every four to six weeks to maintain heating efficiency and avoid calcium deposits in drinks. The combi-boiler should be fitted with a scale inhibitor and serviced annually to check the heat exchanger. Washing-up liquid performs adequately at normal quantities. Taps and shower heads develop moderate limescale deposits over a few weeks; a monthly wipe with white vinegar or a mild descaling product keeps fittings in good condition. Overall, Melksham's water quality is typical for the limestone country of south-west England and demands routine but not intensive descaling attention.