Arbroath Water Hardness & Quality Report (2026)

Arbroath, the historic Angus port town on the North Sea coast south of Montrose — home of the Declaration of Arbroath and famous for its haddock smokies — is supplied by Scottish Water from Lintrathen Reservoir impounded on the Melgam Water in Glen Isla, one of the southern Angus glens that descend from the Grampian Highlands. The Lintrathen catchment drains the Dalradian metamorphic schist, quartzite and phyllite of the inner Angus glens and the Devonian Old Red Sandstone (Strathmore Formation) of the Strathmore valley — ancient and geologically inert rocks that yield virtually zero dissolved mineral content to surface drainage. At 12 mg/L hardness and an extraordinary TDS of only 19.7 mg/L — the lowest in this dataset and among the lowest recorded for any UK public water supply — Arbroath's water is essentially indistinguishable from pure mountain rainfall. Scottish Water treats this supply at Arbroath Water Treatment Works before distribution; chemical treatment here is mainly for microbiological safety, since the water's natural mineral content requires no hardness adjustment.

The Dalradian metamorphic rocks of the inner Angus glens — Neoproterozoic schists, quartzites and metasediments metamorphosed during the Caledonian orogeny — are crystalline, impermeable and entirely devoid of calcium carbonate. Combined with the Devonian Old Red Sandstone of the Strathmore lowlands (a continental fluvial sandstone lacking chalk or limestone), the Lintrathen catchment produces rainfall-quality water of extraordinary purity. A TDS of 19.7 mg/L is lower than many commercially bottled still mineral waters — testament to the Scottish Highlands' geological character as one of the world's great sources of naturally pure soft water.

At 12 mg/L Arbroath's water is exceptionally soft — the absolute practical minimum for a UK public supply. There is no observable limescale in kettles, shower screens, taps or any household appliance. Kettles may run for months or years without any descaling. Washing-up liquid froths abundantly with the smallest drop. Combi-boilers and white goods have zero scaling risk and essentially unlimited lifespans from a scale perspective. The sole caution is that such ultra-soft water is chemically aggressive toward old lead pipework — any pre-1970 lead pipes or lead-solder joints in Arbroath's Victorian fishing-town housing stock should be replaced for health reasons.