Limavady Water Hardness & Quality Report (2026)

Northern Ireland Water supplies Limavady, the County Londonderry market town near the Roe Valley — a pleasant town at the mouth of the Roe Valley with a strong Scottish and Plantation heritage, adjacent to Binevenagh (the dramatic basalt cliff and plateau AONB above Lough Foyle) and the Roe Valley Country Park with its historic linen mill heritage and salmon fishing on the Roe — from Altnaheglish Reservoir on the Binevenagh basalt plateau above the town, treated at Altnaheglish Water Treatment Works. At 41 mg/L (2.9°Clark), Limavady's water is very soft — consistent with the impermeable Basalt (Antrim Lava Group, Paleogene) and Triassic Sherwood Sandstone catchment of the Binevenagh upland that yields very little calcium to surface runoff.

Limavady draws supply from Altnaheglish Reservoir on the Binevenagh plateau — a landscape of Tertiary Basalt (the same basalt formation that creates the Giant's Causeway and the Antrim Plateau) and underlying Triassic sandstone. The impermeable basalt catchment contributes almost no calcium to surface runoff, producing 41 mg/L with TDS 69.5 mg/L — very soft water characteristic of the NI Water north Derry basalt plateau supply, similar to other Antrim Basalt catchment communities.

At 41 mg/L, limescale is a minimal household concern in Limavady. Kettle descaling every two to three months is typically all that is required. The combi-boiler has very low scaling risk. Washing-up liquid lathers very readily. Taps and shower heads accumulate very little limescale. In older Limavady properties with lead service pipes, residents should follow NI Water's advice to run the cold tap briefly before drinking, as soft low-TDS water has increased plumbo-solvent potential — NI Water actively advises this precaution across the soft north Derry supply zone.