Inverness Water Hardness & Quality Report (2026)

Inverness, the Highland capital on the Beauly Firth, is supplied by Scottish Water from Loch Ruthven in the Strathnairn Hills south-east of Inverness and the River Ness catchment system. Loch Ruthven is a small, remote upland loch draining the Moine Schist — ancient Precambrian and Caledonian metamorphic rocks of the central Highlands — a formation that is extremely chemically insoluble. The River Ness drains Loch Ness, fed in turn by the Great Glen catchment draining ancient Moine and Glenfinnan Group metamorphic rocks. These ancient metamorphic basement rocks of the Highlands contribute essentially no dissolved calcium to the runoff. Scottish Water treats supply at its Inverness facilities and distributes to the city. The TDS of only 30 mg/L confirms the exceptional mineral purity of the Inverness Highland supply.

Inverness's exceptionally soft water — 15 mg/L (1.1°Clark) — is one of the softest domestic water supplies in the United Kingdom, reflecting the Moine Schist and Dalradian metamorphic rocks of the central Highland catchments. At this hardness, dissolved calcium is barely detectable. The Drinking Water Quality Regulator for Scotland classifies this supply as very soft.

Limescale is essentially absent in Inverness homes. At 15 mg/L, limescale will not form under any normal domestic circumstances — kettles need descaling perhaps once a year at most and taps, showerheads, and shower screens remain completely clear. Washing-up liquid lathers exceptionally well. The main household consideration at this extreme softness is the water's mildly corrosive potential to copper plumbing — Scottish Water carefully manages pH to protect old pipework. Inverness households in older properties should be aware of the slight risk of copper leaching and should consider a calcite neutraliser filter if concerned.