Ashby-de-la-Zouch Water Hardness & Quality Report (2026)

Severn Trent Water supplies Ashby-de-la-Zouch, the historic market town in north-west Leicestershire — known for its Ashby Castle ruins, Mary Queen of Scots imprisonment, Walter Scott's *Ivanhoe* tournament setting, and its role in the Civil War — from Derwent Valley Reservoirs in the Peak District blended with a large proportion of Permo-Triassic Sandstone (Sherwood Sandstone) groundwater in the north-west Leicestershire distribution zone, treated at Bamford Water Treatment Works. At 244.5 mg/L (17.2°Clark) and a TDS of 724.3 mg/L, Ashby's water is hard with a notably elevated TDS/hardness ratio (3.0) indicating significant sulphate content from Triassic Keuper Marl (Mercia Mudstone) gypsum dissolution in the north Leicestershire–Staffordshire border area.

Ashby-de-la-Zouch lies on the north Leicestershire coal and clay belt where the Triassic Mercia Mudstone (Keuper Marl) with gypsum veins overlies the Carboniferous Coal Measures. Severn Trent Water blends soft Derwent Valley reservoir supply with substantial Triassic Sandstone and Mercia Mudstone groundwater from the east Staffordshire–west Leicestershire Triassic plain, contributing elevated sulphate hardness that raises TDS to 724.3 mg/L against 244.5 mg/L hardness — a characteristic sulphate-type hard water signature from Triassic Mercia Mudstone gypsum dissolution.

At 244.5 mg/L, limescale is a persistent and significant household challenge in Ashby-de-la-Zouch. Kettles should be descaled monthly. The combi-boiler needs a fitted scale inhibitor and annual professional servicing. Washing-up liquid requires more product per wash. Taps and shower heads develop visible white limescale deposits within one to two weeks; a fortnightly wipe with white vinegar or a proprietary descaling product keeps fittings clean. The hard Triassic gypsum-influenced supply at Ashby is a less celebrated aspect of the town than its castles and tournament history.