How we provide clean water

United Utilities provides safe constant water to seven million people in the north west of England. Working around the clock we use technology and the natural water cycle to ensure that homes and businesses receive clean, safe drinking water on tap.

We manage the catchment areas where the water falls as rain to collect our supplies, and we store this water in over 200 reservoirs. Over two thirds of our water comes from upland surface water reservoirs in the Lake District, the Pennines and north Wales. A quarter comes from rivers, such as the Dee, and the rest from boreholes.

This water is treated at one of over 80 water treatment works. The treatment used at our works is designed specifically to treat the raw water arriving from the catchment, so that the clean water leaving the works meets the relevant water quality standards.

All water leaving our works must be disinfected to kill any harmful germs that may be present. All stages of water treatment will remove some of the microorganisms present in the raw water. However, chemical disinfection is still required to ensure that the water is free from harmful bacteria and viruses all the way from the works, right through to the last customer on our network. We do this by the addition of small amounts of chlorine, which is added as the final stage of treatment before the water is piped to our customers. The chlorine levels in the water supply are constantly monitored.

At every stage in its journey from source to your home we sample, analyse, and continually monitor the effectiveness of water treatment in order to provide you with high quality drinking water. In England and Wales, the Drinking Water Inspectorate (DWI) provides independent scrutiny of drinking water quality checking that it meets the standards laid down in law.

However, it is possible that water quality may deteriorate after it leaves our network of pipes because of how it is stored or used in and around the home. The good news is that there are simple measures that you can take to keep your tap water in tip top condition for you and your family.

Our drinking water safety plan provides additional information on how we ensure our customers receive a safe supply of drinking water now and into the future.

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