Weymouth Water Hardness & Quality Report (2026)

Weymouth, the Dorset seaside resort on the English Channel, is supplied by Wessex Water from Sutton Poyntz spring and reservoir north of Weymouth and the broader south Dorset supply network. The Sutton Poyntz source draws from springs at the foot of the South Dorset Ridgeway chalk downland — the Cretaceous Upper Chalk escarpment running east-west behind Weymouth — supplemented by Corfe and Littlemoor reservoirs and some surface water from the Frome and Dorset catchments. The chalk of the Dorset Ridgeway contributes moderately hard calcium-rich water, but the supplementary surface water from non-chalk catchments and Jurassic limestone country of south Dorset dilutes the chalk component, producing a moderately hard blend. The Portland and Purbeck Jurassic Limestone of the nearby Isle of Portland and Purbeck provides an additional moderate calcium source.

Weymouth's hardness of 148.5 mg/L (10.4°Clark) reflects the blend of South Dorset Chalk spring supply and softer surface catchment contributions. The Dorset chalk is somewhat less pure and less productive than the east Kent or south Hampshire chalk, and the significant non-chalk surface water component in the south Dorset supply blend moderates the chalk hardness contribution. The Drinking Water Inspectorate (DWI) classifies this supply as moderately hard.

Limescale is a moderate household concern in Weymouth. At 148.5 mg/L, limescale forms in kettles within three to four weeks and monthly descaling is sensible. Combi-boiler heat exchangers accumulate deposits moderately; annual servicing with a limescale check is recommended. Showerheads and taps develop consistent deposits. Washing-up liquid lathers moderately. Using Calgon monthly in the washing machine and a regular descaling routine is appropriate limescale management for Weymouth households.