Customers whose water is supplied by the Knapp Mill water treatment works in Christchurch might notice that their tap water changes colour slightly in autumn and winter, especially after rainy weather.

This change is easiest to see in white baths or sinks with deep water. There are no particles in the water but there is a slight green/yellow colour which remains even when the system is flushed by letting a tap run.

Long-term solution

We have plans to address this issue in the longer term. We have begun installing advanced treatment technologies at Alderney Water Treatment Facility. We are also planning improvements at the Knapp Mill site. This investment is part of a plan to build state-of-the-art facilities at the two water treatment sites in Bournemouth and Christchurch (Knapp Mill). We’re investing £113 million at Alderney and £85 million at Knapp Mill over the next few years, with the aim of completing the work by 2026.

The delivery of the upgraded Knapp Mill water treatment works will: 

  • improve local drinking water quality
  • improve the security and resilience of the region’s water supply against extreme conditions
  • implement innovative technology to enhance the water treatment process

ensure the environmental impacts of the work have been assessed and improve the site’s ability to attract wildlife by 10% without impacting the natural habitat of the River Avon.