Mendip Water Hardness & Quality Report (2026)

South West Water provides drinking water to over 4 million customers across Devon, Cornwall, Dorset, and Somerset, including the Mendip area in Somerset. The utility primarily draws water from moorland reservoirs and rivers like the River Exe, River Taw, Roadford, Wistman's, and Kennick. Mendip customers likely receive a blend of surface water from these upland sources, which is then treated at facilities such as Chitteringford and Crownhill. These upland sources are located within the high moorlands of Exmoor and Dartmoor National Parks, with rivers flowing towards the Bristol Channel.

Geologically, the water originates from peaty moorland runoff, which has minimal contact with mineral-rich formations. While Carboniferous limestone is present in the Mendip Hills and Devonian slates lie further west, the supply strategy prioritizes surface water from these upland catchments. This approach avoids prolonged interaction with the underlying rocks, unlike groundwater sourced from chalk or limestone aquifers. Consequently, the water picks up very few dissolved minerals, resulting in characteristically soft water with low mineral content.

Because the water is very soft, you'll find virtually no scale buildup in appliances like kettles, boilers, or washing machines, which helps extend their lifespan and reduces the need for frequent descaling. Soap lathers easily, meaning you can use less, and many people notice their skin feels less dry after washing. A water softener isn't necessary here; in fact, the water is already gentle. However, due to the low mineral content, it's a good idea to periodically check pipes for any signs of corrosion. The water quality consistently meets the strict standards set by the Drinking Water Inspectorate, with typical pH levels between 7.0 and 8.0.