Corporate Responsibility

Testing the quality.

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Our drinking water quality is still among the best in the country. In 2017 we continued to provide industry-leading standards of drinking water, passing 99.96 per cent of tests against stringent UK and European criteria. To maintain our high standards, we carry out thousands of tests on water samples routinely collected from our treatment works, as well as our service reservoirs and randomly selected homes and businesses. In 2020 a new approach of measuring compliance is being introduced that will replace the existing measure, and in 2017 we demonstrated a strong performance using this method.

Clean and safe drinking water.

Last year we provided an average of 2.7 billion litres of drinking water to our customers every day. This water was sourced from rivers and boreholes, before being treated at one of our 97 water treatment works, and distributed to our customers through our network of water mains.

Our water quality regulator, the Drinking Water Inspectorate (DWI), uses a measure known as mean zonal compliance to assess drinking water quality. We test 39 different parameters which are used to assess the quality of water across our area of supply. We carry out more than 425,000 tests a year on water samples from source to tap, to make sure our water quality remains among the highest in the world.

Maintaining excellence.

To maintain our high standards of drinking water quality, we’ve continued to focus on identifying areas of our water network where there’s a higher risk from lead pipes. Once we’ve identified these areas, we can remove these pipes as part of a targeted programme. We plan to replace 36,500 lead communication pipes by 2020.

The number of customers who contact us with concerns about drinking water quality remains low, but we know that we can always do more. We’ll continue our ongoing optimisation of our water treatment processes and also targeted flushing of our mains to drive performance in this area.

Lead in drinking water.

Lead pipes may have been used to connect individual properties to our network of mains before the 1970s. We’ve been working hard over many years to mitigate the potential risk to public health from the presence of lead pipes, and we’ve introduced specific initiatives and programmes, agreed with our customers and approved by our regulators, which have been highly successful.

The number of samples above the current drinking water standard has fallen from 10 per cent in 2001 to less than 1.5 per cent in 2017. However, we recognise that there’s still more to do to achieve our objective of removing the risk of lead in drinking water. This will require a long-term approach to ensure the best outcomes for public health, our customers, and future generations. Click on the case study below to find out more.