Knowle Water Hardness & Quality Report (2026)

Severn Trent Water supplies Knowle, the prosperous south Solihull village in the Metropolitan Borough of Solihull — one of the most desirable residential addresses in the West Midlands, a village of Georgian and Victorian houses with a medieval church, the restored Grand Union Canal passing through the adjacent Lapworth area, and outstanding schools that make the south Solihull corridor a popular choice for professional families — from Derwent Valley Reservoirs in the Peak District blended with Permo-Triassic Sherwood Sandstone groundwater in the south Solihull distribution zone, treated at Frankley Water Treatment Works near Birmingham. At 162 mg/L (11.4°Clark), Knowle's water is hard — reflecting the Triassic Sandstone groundwater fraction blended with the soft Derwent Valley reservoir supply in the south Solihull network.

Knowle lies in the south Solihull Arden landscape on the fringe of the Permo-Triassic Sherwood Sandstone plain. Severn Trent supplies from Derwent Valley reservoirs (soft) blended with a proportion of Triassic Sherwood Sandstone groundwater in the Solihull–Knowle distribution zone, producing 162 mg/L with TDS 402 mg/L — hard water with a moderate TDS/hardness ratio (2.48) indicating predominantly carbonate hardness from the Triassic Sandstone, consistent with the south Solihull supply tier from Dorridge through Knowle and Lapworth in the same Severn Trent distribution zone.

At 162 mg/L, limescale is a consistent household challenge in Knowle. Kettles should be descaled monthly. The combi-boiler benefits from 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 moderately hard Triassic supply at Knowle is characteristic of the south Solihull Arden corridor — the Permo-Triassic plain beneath the canal and the meadows delivering consistently mineralised water to the households of one of the Midlands' most sought-after residential villages.