Rawmarsh Water Hardness & Quality Report (2026)

Yorkshire Water supplies Rawmarsh, a former mining and steel town on the northern outskirts of Rotherham in South Yorkshire. The town's water comes from a blend of Pennine upland reservoir supply — drawn from the soft-water catchments of the South Pennines — and groundwater from the Magnesian Limestone (Permian Zechstein) belt east of the coalfield, treated at regional Rotherham area works before distribution. At 123 mg/L (8.6°Clark), Rawmarsh's water is moderately soft, reflecting the dilution of the Magnesian Limestone groundwater component by softer Pennine reservoir sources in the Yorkshire Water distribution network.

The Magnesian Limestone runs north–south through east South Yorkshire immediately east of the coalfield, providing moderate to hard groundwater of calcium and magnesium character. The soft Millstone Grit Pennine reservoir supply from the west significantly dilutes this component in the Rotherham distribution zone. Rawmarsh sits in the interface zone between the coalfield and the limestone belt, where the supply blend strikes a balance that results in moderately soft water — somewhat harder than Nether Edge or Sheffield inner areas, but appreciably softer than the limestone-belt communities to the east.

At 123 mg/L, limescale accumulates gradually in Rawmarsh homes. Descaling the kettle every six to eight weeks is adequate to maintain good performance. The combi-boiler benefits from a fitted scale inhibitor as a precaution, though the hardness level is not severe. Washing-up liquid lathers satisfactorily at normal quantities. Taps and shower heads develop only light limescale deposits over several weeks; a monthly clean with white vinegar or a mild descaling product is generally sufficient to keep fittings in good condition.