Wells Water Hardness & Quality Report (2026)

Bristol Water supplies Wells, England's smallest city and the Cathedral city of Somerset at the foot of the Mendip Hills — a uniquely intimate city whose very name derives from the natural springs (wells) that issue from the Carboniferous Limestone at the base of the Mendips, the springs that fill the moat of the medieval Bishop's Palace and have sustained human settlement here since Roman times — from the Mendip Hills Carboniferous Limestone spring system, treated at Mendip Water Treatment Works. At 157 mg/L (11.0°Clark), Wells's water is hard — reflecting calcium contributions from the Carboniferous Limestone (Carboniferous, Lower and Middle Limestone Series) of the Mendip Hills karst aquifer that directly feeds the famous St Andrew's Spring and the natural spring system at Wells.

Wells sits directly on the Carboniferous Limestone karst spring line at the southern foot of the Mendip Hills — the St Andrew's Spring discharges at the cathedral precinct, fed by the Mendip limestone aquifer. Bristol Water draws from these springs and the broader Mendip karst system, producing 157 mg/L with TDS 379.5 mg/L — hard water with a relatively low TDS/hardness ratio (2.42) confirming predominantly carbonate hardness from the pure Carboniferous Limestone spring system with minimal sulphate, consistent with a direct karst spring supply rather than a deeper gypsum-bearing aquifer contribution.

At 157 mg/L, limescale is a consistent household challenge in Wells. Kettles benefit from descaling every four to six weeks. The combi-boiler should be fitted with a scale inhibitor and serviced annually. Washing-up liquid requires more product per wash. Taps and shower heads develop visible white limescale deposits within one to two weeks; a monthly wipe with white vinegar or a proprietary descaling product keeps fittings clean. Wells's hard limestone supply is a fitting reflection of the city's foundation — the very Carboniferous Limestone springs that give Wells its name and fill the Bishop's Palace moat also mineralise the tap water of every household in England's smallest and most geologically intimate city.