Christchurch Water Hardness & Quality Report (2026)

Christchurch, the historic market town and borough at the confluence of the River Avon and River Stour near the Dorset coast, is served by Bournemouth Water, the regional supplier that is now part of the South West Water group. Supply is drawn from the Hampshire Basin Chalk Aquifer through boreholes in the Bournemouth and Christchurch hinterland, supplemented by abstraction from the River Stour and River Avon, both of which have chalk-fed spring contributions from the Cranborne Chase and Hampshire downs. Treatment is carried out at Alderney Water Treatment Works in Bournemouth and Knapp Mill Treatment Works in Christchurch, with distribution through the Christchurch and Bournemouth coastal network. The River Avon in particular rises in the Hampshire chalk downs and carries moderately hard water from its entire catchment.

The Cretaceous Chalk of the Hampshire and Dorset basin underlies the heathland south of Christchurch at modest depth. Groundwater abstracted from this chalk has dissolved calcium bicarbonate from the chalk matrix over long residence periods, yielding concentrations of around 200–220 mg/L. Surface abstraction from chalk-fed rivers supplements this, contributing further dissolved calcium and producing the blended hardness of 214.5 mg/L recorded in Christchurch. The TDS of 548 mg/L is elevated but moderate, consistent with a chalk groundwater blend that includes some heathland and river-water dilution.

At 214.5 mg/L Christchurch's water is hard and limescale accumulates progressively on household fittings. Kettles should be descaled monthly — a citric acid solution left to soak for 30 minutes dissolves the white mineral crust effectively. Shower screens and glass panels around baths develop a persistent limescale haze that responds well to a diluted white vinegar spray and microfibre cloth. Washing-up liquid consumption is higher than average. Combi-boilers benefit from scale inhibitor cartridges, and washing machines should use a recommended water softener additive in each wash. Christchurch's riverside and harbour character draws visitors, but the local tap water demands attentive appliance care.