Bow Water Hardness & Quality Report (2026)

Thames Water supplies the Bow area of Greater London with water drawn from a blend of surface and underground sources. The utility draws raw water from the River Thames and its associated reservoirs, alongside groundwater from boreholes tapping the London Basin aquifer. These diverse sources are channeled to major treatment works, including Hampton, Walton, and Coppermills, where the water undergoes purification before being distributed to residents.

The Bow water supply is rooted in the London Basin's geological makeup, characterized by Cretaceous Chalk formations overlaid with Tertiary sands and clays. As rainwater filters through these mineral-rich, chalky layers, it naturally picks up dissolved calcium and magnesium. This geological interaction is the primary driver behind the water's classification as hard to very hard, a common trait for supplies in southeast England.

Homeowners in Bow will likely notice limescale deposits forming in appliances like kettles, boilers, and dishwashers due to the water's hardness. Devices that utilize hot water, such as washing machines and combi boilers, can experience reduced efficiency and wear from scale buildup. Regularly descaling with vinegar solutions, using appropriate dishwasher salt, and potentially installing a domestic water softener are effective ways to mitigate these issues and prolong appliance lifespan. Thames Water ensures the water meets UK drinking standards through processes like coagulation, filtration, and disinfection.