Kenilworth Water Hardness & Quality Report (2026)

Kenilworth, the south Warwickshire town renowned for its magnificent Norman and Medieval castle immortalised by Sir Walter Scott, is supplied by Severn Trent Water from the Triassic Sherwood Sandstone Aquifer and Jurassic Lias of south Warwickshire, supplemented by supply from Severn Trent's Midlands distribution network. South Warwickshire sits on the Permo-Triassic Sherwood Sandstone and Keuper Marl (Mercia Mudstone) basin that extends from Coventry south toward Stratford-upon-Avon. Severn Trent's Coventry–Warwickshire supply zone draws on Triassic sandstone boreholes and on the Coventry canal and river abstraction network, distributing treated supply south to Kenilworth. At 207.5 mg/L with TDS 561.5 mg/L (ratio 2.71), Kenilworth's supply shows moderate mineral enrichment — a Triassic character with calcium sulphate from Keuper Marl evaporite interbeds elevating TDS above what carbonate hardness alone would produce. The Lias Clay of south Warwickshire also contributes calcium and sulphate to the supply blend in this corridor between Coventry and Leamington Spa.

The Triassic Sherwood Sandstone and Keuper Marl (Mercia Mudstone Group) of the Coventry–Kenilworth basin are the dominant supply aquifer for south Warwickshire. The Keuper Marl contains gypsum and anhydrite beds that dissolve calcium sulphate into groundwater, producing the elevated TDS-to-hardness ratio (2.71) characteristic of the Midlands Triassic evaporite supply zones. The Jurassic Lower Lias (limestones and clays) south of Kenilworth also contributes moderate carbonate hardness at the margins of the supply zone.

At 207.5 mg/L Kenilworth's water is hard and limescale is a persistent domestic concern. Kettles benefit from monthly descaling with a citric acid tablet. Shower screens develop a calcium film requiring regular white vinegar treatment. Washing-up liquid must be used generously. Combi-boilers benefit from inline scale inhibitor protection and regular servicing. Kenilworth's medieval castle heritage and prosperous Warwickshire market-town character sit above the Triassic basin whose mineral-enriched groundwater defines the domestic water quality of south Warwickshire.