Trowbridge Water Hardness & Quality Report (2026)

Trowbridge, the county town of Wiltshire on the River Biss in the west Wiltshire textile district, is supplied by Wessex Water from the Wiltshire Chalk Aquifer and the River Avon (Bristol Avon) catchment. Wessex Water draws from chalk boreholes in the Cretaceous Chalk of the west Wiltshire chalk country — the chalk of the Marlborough Downs and the Westbury and Bratton chalk escarpment immediately east of Trowbridge — and from the Bristol Avon which drains both chalk and Jurassic limestone country of north Wiltshire and Somerset. The chalk of the Westbury scarp is productive and contributes high dissolved calcium, and the Avon carries chalk spring-fed water from the chalk of north Wiltshire. Wessex Water treats and distributes to Trowbridge from the west Wiltshire chalk and Avon blend.

Trowbridge's hard water — 214.5 mg/L (15.1°Clark) — reflects the Wiltshire Chalk Aquifer and Bristol Avon chalk catchment in Wessex Water's west Wiltshire supply zone. The chalk of west Wiltshire produces consistently hard water across the Wiltshire supply region. The Drinking Water Inspectorate (DWI) classifies this supply as hard.

Limescale is a persistent household challenge in Trowbridge. At 214.5 mg/L, limescale forms in kettles within two to three weeks and monthly descaling is advisable. Combi-boiler heat exchangers accumulate deposits steadily — annual boiler servicing and an in-line scale inhibitor are recommended. Showerheads, taps, and shower screens develop regular deposits. Washing-up liquid lathers poorly. Using Calgon monthly in the washing machine and maintaining a regular descaling routine is important limescale management for Trowbridge households.