Dalkeith Water Hardness & Quality Report (2026)

Scottish Water serves Dalkeith, drawing its supply from upland reservoirs in the Pentland Hills. Key sources include Glencorse Reservoir, Harlaw Reservoir, and Threipmuir Reservoir, supplemented by inputs from the Glencorse Burn catchment. The raw water undergoes comprehensive treatment at the Glencorse Water Treatment Works, a facility employing coagulation, filtration, disinfection, and pH adjustment processes. This treated water is then distributed to more than 200,000 residents across the Lothians region. Dalkeith receives a blended supply originating from these highland sources, channeled through a network of trunk mains.

The Pentland Hills watershed, a roughly 100 km² area of upland moorland situated south of Edinburgh, is the primary feeding ground for Dalkeith's water. This catchment area is geologically underpinned by Lower Carboniferous volcanic rocks, specifically the Pentland Hills Formation, which includes andesitic lavas and tuffs. Overlying these are Devonian sedimentary sequences and glacial deposits. Unlike regions with extensive carbonate aquifers, such as the Cretaceous chalk found elsewhere, this area lacks significant mineral dissolution. Rainwater here percolates quickly through peaty soils and fractured igneous bedrock, resulting in a naturally soft water with low mineral content.

Because the water is very soft, homeowners in Dalkeith will notice excellent lathering with soaps and detergents, and a significant reduction in limescale buildup. Appliances like kettles, boilers, and showerheads will remain cleaner for longer, and the lifespan of washing machines and dishwashers can be extended due to reduced scaling. No water softener is recommended, as the existing water is already optimally soft. However, due to the low mineral buffering, occasional checks for pipe corrosion are advised. Hot water systems will operate efficiently with minimal scale-related maintenance.