Strabane Water Hardness & Quality Report (2026)

Northern Ireland Water supplies Strabane, a market town on the River Foyle at the Tyrone–Donegal border in Derry City and Strabane — historically significant as the ancestral home of American president Woodrow Wilson — from upland reservoirs in the Killeter Forest and Tyrone Mountains (Sperrins foothills) to the east and south, treated at Killeter Water Treatment Works. At 40.5 mg/L (2.8°Clark) and a TDS of just 68.5 mg/L, Strabane's water is very soft, reflecting the acid upland Dalradian Schist and Ordovician geology of the Tyrone upland catchments that drain into the Foyle system.

The Killeter Forest and Tyrone Mountain uplands south of Strabane are underlain by ancient Dalradian Metasediments and Ordovician Schists — calcium-poor, impermeable metamorphic rocks that produce inherently very soft, low-TDS water with minimal mineral loading. Northern Ireland Water draws on these remote upland catchments to supply the Strabane distribution zone with water that is among the softest in Northern Ireland, at 40.5 mg/L with TDS 68.5 mg/L — virtually indistinguishable in character from the comparably soft water at Port Glasgow, Scotland (40.5 mg/L, TDS 77.7 mg/L) sharing the same ancient geological terrain.

At 40.5 mg/L, Strabane's very soft water places minimal limescale demands on appliances. Descaling the kettle every three to four months is typically adequate. The combi-boiler benefits from a standard scale inhibitor as a precaution. Washing-up liquid lathers easily with minimal product. Taps and shower heads stay virtually scale-free with only occasional attention. In older properties, residents should briefly run the cold tap before drinking, as very soft water can be mildly corrosive to lead or copper plumbing — standard Northern Ireland Water guidance for the soft west Ulster supply zones.