Nottingham Water Hardness & Quality Report (2026)

Nottingham's water supply is managed by Severn Trent Water, drawing from a combination of surface abstraction and groundwater sources in the East Midlands. The River Derwent is a primary surface source, abstracted at Ambergate and stored in Carsington Water — a 35-billion-litre reservoir in Derbyshire completed in 1992, Severn Trent's flagship storage facility and one of the largest reservoirs in England. This is supplemented by licensed boreholes into the extensive Triassic Sherwood Sandstone aquifer beneath Nottinghamshire, which provides a reliable baseflow to the city's supply. Water is treated at Severn Trent's treatment works before distribution to Nottingham and the surrounding districts.

Nottingham's hardness of 140 mg/L (9.8°Clark) reflects the mixed geology of its supply catchments. The River Derwent drains from the Peak District moorlands — relatively soft water — but its lower Derbyshire course passes through limestone and shale terrain that adds calcium carbonate. The Sherwood Sandstone aquifer groundwater component carries moderate mineral content from Triassic strata, and Carsington Water's catchment in the Derbyshire limestone fringe adds further hardness. The blended supply sits firmly in the moderately hard classification of the Drinking Water Inspectorate (DWI).

Limescale is a regular feature of life in Nottingham homes. At 140 mg/L, kettles develop a visible white limescale layer within three to five weeks of daily use, and monthly descaling is advisable. Combi-boiler efficiency is meaningfully affected over time — limescale inside the heat exchanger builds steadily, and annual boiler servicing should include an inspection for deposits. Showerheads, taps, and bathroom surfaces show regular limescale build-up, requiring routine descaling with a bathroom spray. Washing-up liquid produces reasonable lather but less than in soft-water cities to the west. Fitting a scale inhibitor cartridge to the boiler cold feed and using Calgon monthly in the washing machine are both sensible precautions for Nottingham households.