Marple Water Hardness & Quality Report (2026)

United Utilities supplies Marple, a scenic Stockport town set at the confluence of the Goyt and Etherow rivers at the gateway to the Peak District — famous for the Marple Locks flight of sixteen locks on the Peak Forest Canal, the most spectacular flight in England — from Peak District Pennine reservoir catchments including Fernilee and Errwood reservoirs in the Goyt Valley, treated at Fernilee Water Treatment Works. At 148.5 mg/L (10.4°Clark), Marple's water is moderately hard — elevated above the very soft Pennine moorland reservoir baseline — reflecting the Carboniferous limestone and gritstone geology of the Goyt Valley catchment.

Marple sits at the edge of the Peak District in the upper Goyt Valley where the Carboniferous Limestone (Dark Peak) and Millstone Grit meet at the southern Pennine fringe. United Utilities' Fernilee and Errwood reservoirs drain catchments with some Carboniferous Limestone influence in the Goyt headwaters, contributing moderate calcium loading to the otherwise soft moorland supply. The resulting 148.5 mg/L with TDS 390.6 mg/L is moderately hard — harder than the pure Pennine Millstone Grit zones — reflecting the Carboniferous Limestone fringe contribution in the upper Goyt catchment.

At 148.5 mg/L, limescale is a noticeable household concern in Marple. Kettles benefit from descaling every four to six weeks. The combi-boiler should be fitted with a scale inhibitor and serviced annually. Washing-up liquid requires slightly more product than in softer areas. Taps and shower heads develop moderate limescale deposits within two to three weeks; a monthly wipe with white vinegar keeps fixtures in good condition. The moderately hard Goyt Valley supply at Marple is a gentle reminder that the Peak District Carboniferous Limestone, which makes the Goyt Valley so scenic, also adds calcium to the water flowing from its rocky catchments.