How we test your water

If you have ever wondered what tests are carried out to make sure your water is safe, here is an A to Z of the substances we check.

Water quality is monitored continuously at all our treatment works and, in the unlikely event of a problem arising at a site, it is shut down automatically.

50,000 samples of water from treatment works, reservoirs and customers’ taps are analysed annually.

Analysis is carried out using sophisticated laboratory instruments and many results are close to the lowest detectable levels.

This analysis covers three areas:

  • physical which examines the basic character and behaviour of water
  • chemical which measures the level of specific substances
  • microbiological which ensures that no harmful micro-organisms are present.

The following substances are tested: