Guisborough Water Hardness & Quality Report (2026)

Northumbrian Water supplies Guisborough, a market town and historic priory settlement in Redcar and Cleveland at the foot of the Cleveland Hills escarpment. Supply is drawn from Scaling Dam Reservoir on the eastern moors of the North York Moors National Park and from catchments in the Cleveland Hills, treated at Scaling Dam Water Treatment Works before distribution across the Cleveland plain. At 141 mg/L (9.9°Clark), Guisborough's water is moderately soft, reflecting a blend of upland moorland runoff from the sandstone and shale Cleveland Hills with minor groundwater contributions from the Jurassic limestone and Permian Magnesian Limestone belts to the east.

The North York Moors above Guisborough are underlain by Jurassic Oolitic Limestone, shales, and Deltaic Series sandstones — formations of mixed calcium carbonate solubility. The moorland runoff contains some dissolved calcium from the Jurassic limestone horizons in the upper sequences, but the overall catchment character is moderately soft compared to the deep chalk springs further south. The blend of moorland surface water and minor limestone groundwater components produces the moderately soft 141 mg/L supply typical of communities at the Moors escarpment foot.

At 141 mg/L, Guisborough's water is moderately soft with manageable limescale demands. Descaling the kettle every six to eight weeks is typically adequate. The combi-boiler benefits from a fitted scale inhibitor as a precaution. Washing-up liquid lathers satisfactorily at everyday quantities. Taps and shower heads develop only light limescale deposits over several weeks; a monthly wipe with white vinegar keeps fixtures in good condition. The moderately soft supply from the North York Moors is considerably gentler on appliances than the chalk supplies of south-east England.