Dursley Water Hardness & Quality Report (2026)

Severn Trent Water supplies Dursley, a small town at the foot of the Cotswold escarpment above the Severn Vale in south Gloucestershire, from the River Severn abstraction at Mythe near Tewkesbury blended with Cotswold Oolite (Jurassic Inferior Oolite and Great Oolite) limestone spring and groundwater, treated at Mythe Water Treatment Works before distribution across south Gloucestershire. At 183 mg/L (12.8°Clark), Dursley's water is moderately hard, reflecting a blend of the Severn river supply with the calcareous Cotswold limestone aquifer that underlies the escarpment and dip slope directly above the town.

Dursley sits at the immediate foot of the Cotswold escarpment where the Inferior Oolite and Lower Lias limestones create a prominent limestone bench above the Severn Vale. The Cotswold Oolite aquifer — the Great Oolite and Inferior Oolite Jurassic limestone that forms the classic Cotswold Hills — discharges hard, calcium-rich spring water at the escarpment foot around Dursley, Uley, and Slimbridge. This spring water, combined with the moderately hard River Severn supply from Mythe, produces the characteristic moderately hard 183 mg/L supply with TDS 474.2 mg/L that is typical of communities at the Cotswold scarp foot in south Gloucestershire.

At 183 mg/L, limescale is a noticeable household concern in Dursley. 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 supply is characteristic of the Cotswold fringe and Severn Vale communities in Gloucestershire where river and limestone spring sources blend.