Chippenham Water Hardness & Quality Report (2026)

Chippenham, in north Wiltshire on the Bristol Avon, is supplied by Wessex Water from the North Wiltshire Chalk Aquifer and the River Avon (Bristol Avon) catchment. Wessex Water draws from chalk boreholes in the Cretaceous Chalk of the Marlborough Downs to the south-east of Chippenham — the Wiltshire chalk downland of Pewsey Vale, Savernake Forest, and the Marlborough Downs — and from the Bristol Avon, which carries dissolved calcium from the Jurassic limestone country of the Cotswolds to the north and the chalk country to the south. The chalk of north Wiltshire contributes substantial dissolved calcium, and the Avon carries further Jurassic limestone calcium, combining to produce a moderately hard supply typical of the north Wiltshire supply zone.

Chippenham's hardness of 194 mg/L (13.6°Clark) reflects the North Wiltshire Chalk Aquifer and Bristol Avon Jurassic/chalk limestone chemistry in Wessex Water's north Wiltshire supply zone. The Drinking Water Inspectorate (DWI) classifies this supply as moderately hard.

Limescale is a regular household concern in Chippenham. At 194 mg/L, limescale forms in kettles within three to four weeks and monthly descaling is sensible. Combi-boiler heat exchangers accumulate deposits at a moderate rate; annual servicing is recommended. Showerheads and taps develop consistent deposits. Washing-up liquid lathers moderately. Using Calgon monthly in the washing machine and a regular descaling routine is appropriate limescale management for Chippenham households on the Wessex Water north Wiltshire chalk supply.