Derby is supplied by Severn Trent Water. The water is moderately hard (145 mg/L CaCO₃), meaning it has moderate mineral content — some limescale buildup over time. Enter your postcode for your exact zone's full report.
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Tap water in Derby is provided by Severn Trent Water, which serves East Midlands. The water in this area is classified as moderately hard, with a typical hardness of around 145 mg/L CaCO₃. Some limescale buildup is normal, particularly on kettles and showerheads.
UK tap water is among the safest in the world, with over 99.9% of tests passing legal standards each year. However, hardness levels, trace contaminants, and the presence of disinfection byproducts like trihalomethanes (THMs) vary significantly by zone — even within the same city. That's why it's worth checking your specific postcode.
Derby's water hardness of approximately 145 mg/L CaCO₃ places it in the moderately hard category. Soft water in Derby is a result of the local geology and supply sources rather than chalk or limestone.
For context, hardness below 60 mg/L is considered very soft, 60–120 is soft, 120–180 is slightly hard, 180–250 is moderately hard, 250–310 is hard, and above 310 mg/L is very hard. The UK average is around 150–200 mg/L.
UK tap water is safe to drink straight from the tap without filtration. With soft water like Derby's, filtration is less of a necessity for limescale — but a good quality filter jug can still improve taste by reducing chlorine and trace compounds. Reverse osmosis systems remove the widest range of contaminants including nitrates, THMs, and any trace PFAS compounds.
Enter your postcode above to see zone-specific data — hardness, nitrates, lead, chlorine, fluoride and more — directly from Severn Trent Water's annual compliance report.
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