Kendal Water Hardness & Quality Report (2026)

Kendal, the south Cumbrian market town on the River Kent known as the 'Auld Grey Town' for its limestone buildings, is served by United Utilities. Supply draws primarily on Killington Reservoir impounded on a headwater tributary of the upper Kent valley in the Howgill Fells and Shap Fells fringe, supplemented by transfers from the Thirlmere Aqueduct and Haweswater Aqueduct carrying Lake District water south through Cumbria. Water is treated at Watchgate Water Treatment Works south of Shap before distribution through the south Cumbria network. The hardness of 122.5 mg/L is somewhat elevated compared with pure Lake District upland water, reflecting the influence of Carboniferous Great Scar Limestone that outcrops prominently at Scout Scar and the Kendal Fell immediately west of town — the limestone country of the Kent valley fringe that also underlies the grey building stone for which the town is named.

The Carboniferous Great Scar Limestone — the pale grey cliff-forming limestone of the Yorkshire Dales and south Lake District fringe — crops out on the limestone escarpment directly above Kendal. Where the River Kent's tributaries drain across or through this limestone belt, they acquire dissolved calcium bicarbonate, raising hardness above the otherwise soft Lake District baseline. The Ordovician and Silurian greywacke and slate of the Howgill Fells that forms the primary Killington catchment yield soft water, but the limestone fringe contribution elevates total hardness to 122.5 mg/L in the Kendal supply zone. The TDS of 331.6 mg/L is higher than typical purely moorland water, reflecting this limestone influence.

At 122.5 mg/L Kendal's water is moderately soft with mild limescale tendencies. Kettles need descaling every six to eight weeks — a citric acid tablet left in a boiled kettle for an hour keeps elements clean. Shower heads benefit from occasional soaking in white vinegar to maintain good jet flow. Washing-up liquid lathers well. Combi-boilers and white goods face modest scaling risk and routine maintenance is straightforward. Kendal's grey limestone buildings mirror the character of its water — the same limestone geology that gives the town its distinctive appearance contributes the modest calcium content in the tap.