Tranent Water Hardness & Quality Report (2026)

Scottish Water supplies Tranent, the East Lothian town in the Musselburgh and Prestonpans coastal hinterland — a former coalmining and salt-panning community between the Lammermuir Hills and the Firth of Forth, best known historically for the Battle of Prestonpans in 1745 when Bonnie Prince Charlie's Jacobite army defeated the government forces — from Whiteadder Reservoir in the Lammermuir Hills, impounded on the Whiteadder Water catchment near Gifford, treated at Whiteadder Water Treatment Works. At 61.5 mg/L (4.3°Clark), Tranent's water is very soft — consistent with the Ordovician and Silurian greywacke and shale bedrock of the Lammermuir Hills that produces naturally soft, low-TDS reservoir water.

Transent draws supply from Whiteadder Reservoir whose catchment lies in the Lammermuir Hills — a rolling plateau of Ordovician–Silurian greywacke (Caledonian turbidite sequences) that is broadly impermeable and strongly calcium-limited. The Lammermuir bedrock weathers very slowly and contributes minimal calcium to surface runoff, yielding 61.5 mg/L with TDS 130.7 mg/L at Tranent — very soft water characteristic of the East Lothian Whiteadder supply zone that serves the coastal strip from Musselburgh through Tranent and Prestonpans to Haddington on the same Whiteadder distribution network.

At 61.5 mg/L, Tranent's very soft Lammermuir water is comfortable for domestic use with very modest limescale demands. Descaling the kettle every two to three months is typically adequate. The combi-boiler needs only a simple scale inhibitor as a standard precaution. Washing-up liquid lathers well at everyday quantities. Taps and shower heads remain relatively scale-free with only occasional light maintenance. In older Tranent properties — particularly former colliery and agricultural workers' housing with ageing copper or lead pipework — running the cold tap briefly before drinking is the standard Scottish Water precautionary guidance for the soft East Lothian Whiteadder supply zone.