Alton Water Hardness & Quality Report (2026)

South East Water supplies Alton, Hampshire, drawing water from groundwater boreholes in the chalk aquifers of the Hampshire Downs. Key local sources include Selborne and Teg Down, managed by the utility and treated at facilities like the Alton Water Treatment Works. Here, water undergoes filtration, disinfection via chlorination, and pH adjustment before distribution to residents in Alton and surrounding communities within East Hampshire. The watershed is characterized by the Cretaceous Upper Chalk Group, a thick limestone formation that acts as a significant aquifer.

This particular geology, the Cretaceous Upper Chalk Group, is a porous and permeable limestone. Rainfall percolates deeply, spending a long time in contact with the bedrock. This extended interaction dissolves considerable amounts of calcium and magnesium minerals from the chalk, resulting in water that is notably hard. Unlike surface water sources found in softer, peaty upland areas, this groundwater picks up substantial mineral content as it moves through the extensive underground rock formations.

Homeowners in Alton often notice heavy limescale buildup on appliances such as kettles, boilers, and showerheads, which can reduce their efficiency and shorten their lifespan. You might see white deposits or clogged pipes. To combat this, regularly descaling with vinegar or citric acid and keeping boiler temperatures below 60°C can help. Many residents find that installing a whole-house water softener is the most effective solution for preventing scale and protecting their plumbing and appliances. While the water meets UK standards, South East Water advises using cold kitchen taps for drinking and flushing stagnant water to minimize potential exposure to any trace elements. The Drinking Water Inspectorate monitors quality, or DWI, monitors quality, and specific test results can be found on the utility's website.