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Environmental performance

Protecting rivers and the environment

Water companies treat water used from your homes and return it safely to rivers and the sea. English and Welsh water companies receive an overall rating for this: the Environmental Performance Assessment.

Source: Environment Agency and Natural Resources Wales; England and Wales, Jan 2022 – Dec 2022 Three out of four star rating awarded by Environment Agency and Natural Resources Wales
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What is measured in the Environmental Performance Assessment?

The Environmental Performance Assessment is a basket of seven measures on how well companies protect the environment – companies get an overall “star” rating out of four stars.

The four ratings are: leading (4 stars), good (3 stars), requires improvement (2 stars) and poor (1 star). From 2021, the thresholds for star ratings have been tightened to push improvements in water company performance, so ratings from 2021 are not directly comparable with ratings in previous years.

Three of the measures are shown separately on DiscoverWater.co.uk:

  • how many times there were unexpected releases of contaminants from companies’ systems
  • whether companies are meeting their environmental permit conditions
  • whether companies are on track to make the environmental improvements they said are obliged to deliver

The other four measures are how many times there were more serious releases of contaminants from companies’ systems, the availability of water for public supply, a measure of satisfactory sludge use and disposal, and what proportion of incidents are being reported by companies themselves rather than by others.

EPA star rating (out of four stars)

The Environment Agency and Natural Resources Wales give companies a star rating out of four for their overall performance in protecting the environment.

This is how companies scored in the latest year.

      EPA star rating (out of four stars)

      Source: Environment Agency & Natural Resources Wales

      EPA star rating (out of four stars)

      The Environment Agency and Natural Resources Wales give companies a star rating out of four for their overall performance in protecting the environment. This is how companies scored in the last three years. From 2021, the thresholds for star ratings have been tightened to push improvements in water company performance, so scores from 2021 are not directly comparable with scores in previous years.

          EPA star rating (out of four stars)

          Source: Environment Agency & Natural Resources Wales

          1,747 Incidents caused by unexpected release of contaminants

          Source: Environment Agency and Natural Resources Wales; England and Wales, Jan 2022 – Dec 2022

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          Why might performance vary?

          Companies in different parts of the country have different challenges they need to meet. They invest many millions each year in measures to protect the environment, but in some cases, it can take a few years before the benefits of investment are realised and have taken full effect. Performance will also vary due to weather as heavy rain is more likely to cause sewers to overflow.

          The graph shows how often a contaminant got into a river, lake or the sea due to unexpected releases from companies’ systems in the latest year. So that companies of different sizes can be compared, the graphs show the number of incidents per 10,000 km of sewer.


          Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

              Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

              Source: Environment Agency & Natural Resources Wales

              The graph shows how often a contaminant got into a river, lake or the sea from companies’ systems in the last three years. So that companies of different sizes can be compared, the graphs show the number of incidents per 10,000 km of sewer.


              Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

                  Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

                  Source: Environment Agency & Natural Resources Wales

                  98.9% Level of compliance with environmental permit conditions

                  Source: Environment Agency and Natural Resources Wales; England and Wales, Jan 2022 – Dec 2022

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                  Conditions vary between water treatment and sewage treatment works depending on the environmental sensitivity of the water body receiving the water or treated sewage.

                  Why might performance vary?

                  Companies in different parts of the country have different challenges they need to meet. They invest many millions each year in measures to protect the environment, but in some cases, it can take a few years before the benefits of investment are realised and have taken full effect.

                  The graph shows how well companies did against their environmental permit conditions in the latest year, as a percentage score.


                  Percentage of environmental permit conditions met (%)

                      Percentage of environmental permit conditions met (%)

                      Source: Environment Agency & Natural Resources Wales

                      The graph shows how well companies did against their environmental permit conditions in the last three years, as a percentage score.


                      Percentage of environmental permit conditions met (%)

                          Percentage of environmental permit conditions met (%)

                          Source: Environment Agency & Natural Resources Wales

                          99.6% Environmental improvement measures completed

                          Source: Environment Agency and Natural Resources Wales; England and Wales, Jan 2022 – Dec 2022

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                          Why might performance vary?

                          Each company has a different environmental improvement programme, agreed with their customers and the Environment Agency or Natural Resources Wales, to meet the environmental needs in their area.

                          Companies aim to deliver their environmental improvement programmes to the agreed schedule. Sometimes investment will be brought forward to deliver earlier environmental benefits, and sometimes particular schemes are delayed for a variety of reasons. Occasionally schemes will be cancelled if companies and the Environment Agency agree that there are better ways of doing what needs to be done.

                          The graph shows whether companies are on track to complete their planned environmental improvements, as a percentage score.

                          Percentage of environmental improvement measures completed based on National Environment Programme (%)

                              Percentage of environmental improvement measures completed​ based on National Environment Programme​ (%)

                              Source: Environment Agency & Natural Resources Wales

                              The graph shows whether companies are on track to complete their planned environmental improvements, as a percentage score. This graph shows the performance in the last three years.


                              Percentage of environmental improvement measures completed based on National Environment Programme (%)

                                  Percentage of environmental improvement measures completed​ based on National Environment Programme​ (%)

                                  Source: Environment Agency & Natural Resources Wales

                                  Click for company comparison Close Panel
                                  Click for company comparison Close Panel
                                  Click for company comparison Close Panel

                                  Why might performance vary?

                                  Companies in different parts of the country have different challenges they need to meet. They invest many millions each year in measures to protect the environment, but in some cases, it can take a few years before the benefits of investment are realised and have taken full effect. Performance will also vary due to weather as heavy rain is more likely to cause sewers to overflow.

                                  The graph shows how often a contaminant got into a river, lake or the sea due to unexpected releases from companies’ systems in the latest year. So that companies of different sizes can be compared, the graphs show the number of incidents per 10,000 km of sewer.


                                  Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

                                      Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

                                      Source: Environment Agency & Natural Resources Wales

                                      The graph shows how often a contaminant got into a river, lake or the sea from companies’ systems in the last three years. So that companies of different sizes can be compared, the graphs show the number of incidents per 10,000 km of sewer.


                                      Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

                                          Number of incidents caused due to unexpected release of contaminants (per 10,000 km of sewers)

                                          Source: Environment Agency & Natural Resources Wales

                                          Conditions vary between water treatment and sewage treatment works depending on the environmental sensitivity of the water body receiving the water or treated sewage.

                                          Why might performance vary?

                                          Companies in different parts of the country have different challenges they need to meet. They invest many millions each year in measures to protect the environment, but in some cases, it can take a few years before the benefits of investment are realised and have taken full effect.

                                          The graph shows how well companies did against their environmental permit conditions in the latest year, as a percentage score.


                                          Percentage of environmental permit conditions met (%)

                                              Percentage of environmental permit conditions met (%)

                                              Source: Environment Agency & Natural Resources Wales

                                              The graph shows how well companies did against their environmental permit conditions in the last three years, as a percentage score.


                                              Percentage of environmental permit conditions met (%)

                                                  Percentage of environmental permit conditions met (%)

                                                  Source: Environment Agency & Natural Resources Wales

                                                  Why might performance vary?

                                                  Each company has a different environmental improvement programme, agreed with their customers and the Environment Agency or Natural Resources Wales, to meet the environmental needs in their area.

                                                  Companies aim to deliver their environmental improvement programmes to the agreed schedule. Sometimes investment will be brought forward to deliver earlier environmental benefits, and sometimes particular schemes are delayed for a variety of reasons. Occasionally schemes will be cancelled if companies and the Environment Agency agree that there are better ways of doing what needs to be done.

                                                  The graph shows whether companies are on track to complete their planned environmental improvements, as a percentage score.

                                                  Percentage of environmental improvement measures completed based on National Environment Programme (%)

                                                      Percentage of environmental improvement measures completed​ based on National Environment Programme​ (%)

                                                      Source: Environment Agency & Natural Resources Wales

                                                      The graph shows whether companies are on track to complete their planned environmental improvements, as a percentage score. This graph shows the performance in the last three years.


                                                      Percentage of environmental improvement measures completed based on National Environment Programme (%)

                                                          Percentage of environmental improvement measures completed​ based on National Environment Programme​ (%)

                                                          Source: Environment Agency & Natural Resources Wales

                                                          • This is a basket of measures on how well companies protect the environment. The measures cover things like how companies have prevented sewage getting into rivers, do they treat and dispose of sewage properly and do they have good equipment and processes to treat sewage.

                                                          • The Environment Agency and Natural Resources Wales collect the data from their own regulatory activities and from companies on how they have performed on the measures mentioned above. Both regulators then use this data to form a scorecard and give an overall assessment.

                                                            From 2021, the thresholds for star ratings have been tightened to push improvements in water company performance, so scores from 2021 are not directly comparable with scores in previous years.

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