Canford Heath Water Hardness & Quality Report (2026)

Bournemouth and West Hampshire Water (part of the South West Water group) supplies Canford Heath, a large residential estate in the borough of Poole in the Bournemouth, Christchurch and Poole unitary authority, from the River Stour abstracted at Knapp Mill near Christchurch and from Dorset Chalk borehole sources, treated at Knapp Mill Water Treatment Works. At 153 mg/L (10.7°Clark), Canford Heath's water is moderately hard — softer than Wimborne Minster (287 mg/L) further up the Stour, reflecting the moderating effect of the River Stour surface water diluting the concentrated chalk borehole supply fraction at this point in the distribution network.

The River Stour at Knapp Mill is a chalk-fed river drawing its calcium content from the Dorset Chalk plateau of Cranborne Chase and the Hampshire Chalk of the Fordingbridge area, but at this lower catchment point the river is more diluted and carries lower hardness than the confined chalk borehole water upstream. Bournemouth Water blends the Stour surface supply with chalk borehole contributions from the Tertiary sand and clay-overlain confined chalk aquifer beneath the Poole Basin, producing the 153 mg/L with TDS 343 mg/L at Canford Heath — notably softer than the pure chalk borehole zones to the north and north-east.

At 153 mg/L, limescale is a noticeable domestic concern in Canford Heath. 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 slightly more product than in softer areas. Taps and shower heads develop moderate limescale deposits within two to three weeks; a monthly wipe with white vinegar keeps fixtures in good condition. The moderately hard Stour-chalk blend supply is characteristic of the Poole basin communities along the Stour and Avon corridors of the south Dorset coast.