Preston Water Hardness & Quality Report (2026)

United Utilities supplies Preston's water, drawing from a mix of upland reservoirs and boreholes across the North West. Water treatment takes place at Preston Treatment Works, serving the City Centre supply zone. This network is one of the UK's largest, delivering water to millions. The Preston supply area benefits from the North West's varied hydrogeology, with most raw water coming from upland surface reservoirs. These reservoirs are primarily composed of Carboniferous-age Millstone Grit and related formations, naturally yielding very soft water.

Conversely, boreholes located in the southern part of the region tap into aquifers that provide reasonably hard water. United Utilities strategically blends these softer upland supplies with the harder groundwater. This blending process balances the overall supply and meets customer demand, ultimately resulting in a slightly hard water profile. This characteristic reflects the diverse geological makeup of the region, from the soft water sources in the uplands to the harder aquifers found further south.

Homeowners in Preston might observe some minor limescale accumulation on kettles and taps due to the slightly hard water classification. While not typically problematic, a regular descaling routine can help manage this. Appliances like dishwashers and washing machines may experience slight scaling, but routine cleaning usually suffices. Installing a water softener is an optional consideration for those particularly sensitive to limescale or aiming to maximize appliance longevity; if a softener is used, it's recommended to install it after the drinking water tap to retain beneficial minerals.