Sinfin Water Hardness & Quality Report (2026)

Severn Trent Water supplies Sinfin, a district within Derby in the East Midlands, drawing its water from the Elan Valley reservoirs located in mid-Wales. These extensive reservoirs, including Caban Coch, Garreg Ddu, and Pen-y-Garreg, are fed by the River Elan and River Claerwen catchments. The water undergoes a significant journey, traveling through the historic Elan aqueduct, a gravity-fed conduit completed in 1904, to reach the Frankley Water Treatment Works near Birmingham. Here, it's treated using coagulation, filtration, chlorination, and fluoridation before distribution to the network serving Derby's residents and millions of others.

The watershed itself covers a vast area of upland moorland and forestry in Powys, Wales, and is underlain by geology primarily composed of Lower Silurian grits, shales, and Ordovician volcanic rocks. These are often covered by glacial till and peat, but importantly, they do not form any significant aquifer. This non-carbonate bedrock, combined with short flow paths through acidic soils, results in water that is naturally very soft. It has low alkalinity and minimal dissolved solids, giving it a pristine, low-mineral profile shaped by the region's impermeable geology and abundant rainfall.

As a soft water area, Sinfin homeowners will notice minimal limescale buildup, which helps protect appliances like boilers and kettles from scaling and can extend their operational life. You'll also find that soap lathers easily, meaning less detergent is needed for laundry and bathing. While soft water is generally beneficial for appliances, the low buffering capacity can slightly increase the risk of pipe corrosion, potentially leading to increased lead leaching from older plumbing. Severn Trent advises regular flushing of taps, especially after periods of disuse. The utility consistently meets UK Drinking Water Inspectorate standards, with treatments at Frankley including ozone disinfection and granular activated carbon filtration to ensure a safe and reliable supply.