Oakwood Water Hardness & Quality Report (2026)

Severn Trent Water supplies Oakwood, a residential suburb on the north-east fringe of Derby — one of the city's newer planned residential developments, adjacent to the Nottingham Road corridor and the Derbyshire countryside fringe — from Derwent Valley Reservoirs in the Peak District via the north Derby distribution zone, treated at Bamford Water Treatment Works in the upper Derwent. At 112.5 mg/L (7.9°Clark), Oakwood's water is slightly hard — relatively soft for an East Midlands city — reflecting the dominance of the soft Derwent Valley Millstone Grit and gritstone upland reservoir supply in the north Derby distribution zone.

Oakwood lies in the north Derby distribution sub-zone where Severn Trent Water delivers predominantly soft Derwent Valley reservoir supply from the Peak District moorland catchments above Bamford. The Howden, Derwent, and Ladybower reservoirs drain acid Millstone Grit uplands with minimal calcium carbonate, producing naturally soft water. A modest proportion of Triassic Sherwood Sandstone groundwater from the east Derbyshire plain adds calcium to produce 112.5 mg/L with TDS 252.2 mg/L — slightly hard, distinctly softer than the moderately hard east Derby sub-zone at Chaddesden (186.5 mg/L).

At 112.5 mg/L, limescale is a moderate and manageable domestic concern in Oakwood. Descaling the kettle every six to eight weeks is typically adequate. The combi-boiler benefits from a standard scale inhibitor as a precaution. Washing-up liquid lathers adequately at everyday quantities. Taps and shower heads develop light deposits over several weeks; a monthly wipe with white vinegar keeps fixtures in good condition. The slightly hard Derwent Valley-dominant supply in north Derby is notably softer than many East Midlands cities, reflecting the Peak District moorland reservoir heritage of the Derby water network.