Taunton Water Hardness & Quality Report (2026)

Taunton, the county town of Somerset on the River Tone, is supplied by Wessex Water from the Mendip Hills reservoir system. Wessex Water's principal sources for Somerset include Cheddar Reservoir at the base of the Mendip escarpment — fed by rivers draining the Carboniferous Dinantian Limestone plateau of the Mendips — and Blagdon Lake in the Mendip foothills. These sources supply a highly calcium-rich water from the Mendip limestone catchment, treated at Wessex Water's facilities before distribution south to Taunton via the Somerset Levels network. Supplementary supply from Durleigh Reservoir near Bridgwater and the River Tone catchment adds further calcium from the Jurassic Lias limestone country of the Vale of Taunton Deane.

Taunton's hardness of 240 mg/L (16.8°Clark) is high for a Somerset town, reflecting the strong Carboniferous Limestone and Jurassic Lias chemistry in the Wessex Water Somerset supply blend. Cheddar Reservoir is fed by streams draining the Mendip limestone plateau — the same carbonate rock responsible for Cheddar Gorge's deep dissolution features — producing very high calcium concentrations. The blend with more moderate Jurassic Lias and River Tone catchment contributions yields a consistently hard supply. The Drinking Water Inspectorate (DWI) classifies this supply as hard.

Limescale is a persistent household challenge in Taunton. At 240 mg/L, limescale forms in kettles within two to three weeks and fortnightly or monthly descaling is advisable. Combi-boiler heat exchangers accumulate deposits steadily — annual boiler servicing and fitting an in-line scale inhibitor are strongly 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 essential limescale management for Taunton households on the Mendip limestone supply.