Water quality

We have amongst the highest water quality in the UK.

Water quality

All drinking water in the UK has to comply with stringent standards set by the Water Supply (Water Quality) Regulations, which incorporate the requirements of the European Drinking Water Directive.

Compliance in England and Wales is strictly monitored by the Drinking Water Inspectorate (DWI). The DWI
independently reviews all water companies' test results and audits their water quality testing laboratories.

They publish an annual report which summarises the water quality standards achieved by regions and individual companies. This allows consumers to check their water supplier's performance and to find out about events and incidents which must be notified to the DWI.

Each year, we carry out approximately 120,000 tests on around 13,000 samples taken from every point in our supply chain. Water sources, treatment works, storage reservoirs and randomly selected customer taps all come under scrutiny. We regularly achieve more than 99.5 per cent compliance with industry standards.

Our laboratory is UKAS accredited, an internationally recognised quality standard which covers all aspects of activity from sampling and analysis through to reporting the results.

Explore more about water quality

Graphic for water quality brochure 
Our annual water quality report for 2019

For more information about water quality and how we comply with industry standards, download our annual water quality report for 2019.

Read our report for 2019

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