Stockton-on-Tees Water Hardness & Quality Report (2026)

Northumbrian Water supplies Stockton‑on‑Tees with water drawn from a mix of sources. These include surface water from reservoirs and rivers, alongside groundwater from local aquifers. This blended supply is treated at regional water treatment works before reaching homes and businesses across County Durham, North Yorkshire, and the Tees Valley. The local watershed feeds into the River Tees and its tributaries, with catchments spanning both upland and lowland terrains. The treatment processes employed aim to meet stringent UK drinking‑water standards, involving steps like coagulation, filtration, and disinfection.

The water's journey begins underground, flowing through Permian and Triassic sandstones and mudstones. These sedimentary rock formations are the source of the water's mineral content. As water percolates through these layers, it dissolves moderate amounts of minerals like calcium and magnesium. This geological interaction results in a moderately mineralised supply, classifying the water as moderately hard rather than very soft or exceptionally hard.

Homeowners in Stockton‑on‑Tees might observe some limescale accumulation on appliances such as kettles and showerheads, as well as on heating elements. Regular descaling of kettles and cleaning of fixtures can help keep these items running efficiently. While a water softener isn't strictly necessary, it could prove beneficial for those seeking to reduce scale and enhance soap lathering. The Northumbrian Water supply is generally compliant with lead and copper limits, although older properties with lead plumbing should be checked. The water's pH is adjusted to be slightly alkaline, which helps protect pipes from corrosion.