Environmental performance assessment (EPA) star ratings 2011 to 2023
Published 23 July 2024
Applies to England
© Crown copyright 2024
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This publication is available at https://www.gov.uk/government/publications/water-and-sewerage-companies-in-england-environmental-performance-report-2023/environmental-performance-assessment-epa-star-ratings-2011-to-2023
We introduced the EPA in 2011 as a tool for comparing performance between water companies and across years for several core requirements.
Every 5 years we review how we report on water company environmental performance and review the EPA. We deliberately tighten our metrics over time in response to investment made in industry assets and public expectation of better performance. Please refer to our EPA metric guide for more information on our regulation and how we set targets for water companies. We share our EPA methodology with the water companies.
We have published our annual Environmental performance of the water and sewerage companies in 2023 report. This document provides a summary of the EPA star ratings since 2011. All water companies can achieve 4 stars (industry leading).
From 2011 to 2023:
- South West Water has consistently been rated 1 star (poor) or 2 stars (requiring improvement), and Southern Water has mostly been rated 1 star or 2 stars
- 5 water companies have achieved 4 stars (industry leading) – all at least twice, but only Severn Trent Water has shown they can achieve this consistently (Table 1)
- the trend in sector star ratings is stable (neither improves nor deteriorates) with an average of 25 stars (out of 36) – ranging between 22 stars and 30 stars (Table 1 and Figure 1)
It is not straightforward to make a direct comparison across the lifespan of the EPA due to changes in our expectations and EPA metric definitions. However, to review if there have been EPA performance improvements over time, we have applied the 2023 methodology to all previous years of EPA data (Figure 1). This shows an improving trend in sector star ratings from 11 stars to 25 stars (out of 36). This indicates some sector improvements in EPA performance over time, however the majority of water companies continue to underperform and are not meeting our expectations.
Table 1. EPA performance star ratings for the 9 water and sewerage companies 2011 to 2023 (maximum of 4 stars per year)
2011 to 2015 data
| Year | 2011 | 2012 | 2013 | 2014 | 2015 |
|---|---|---|---|---|---|
| Anglian Water | 3 | 3 | 3 | 3 | 3 |
| Northumbrian Water | 2 | 3 | 3 | 3 | 3 |
| Severn Trent Water | 3 | 3 | 4 | 3 | 4 |
| Southern Water | 2 | 2 | 1 | 2 | 3 |
| South West Water | 1 | 2 | 1 | 2 | 1 |
| Thames Water | 3 | 3 | 2 | 3 | 3 |
| United Utilities | 3 | 3 | 3 | 3 | 4 |
| Wessex Water | 4 | 4 | 3 | 3 | 4 |
| Yorkshire Water | 2 | 2 | 3 | 4 | 3 |
| Sector | 23 | 25 | 23 | 26 | 28 |
2016 to 2020 data
| Year | 2016 | 2017 | 2018 | 2019 | 2020 |
|---|---|---|---|---|---|
| Anglian Water | 3 | 3 | 3 | 2 | 3 |
| Northumbrian Water | 2 | 2 | 4 | 2 | 4 |
| Severn Trent Water | 3 | 4 | 3 | 4 | 4 |
| Southern Water | 3 | 3 | 2 | 1 | 2 |
| South West Water | 2 | 2 | 2 | 2 | 2 |
| Thames Water | 2 | 3 | 3 | 3 | 3 |
| United Utilities | 4 | 4 | 3 | 3 | 4 |
| Wessex Water | 4 | 4 | 3 | 4 | 4 |
| Yorkshire Water | 3 | 3 | 2 | 3 | 4 |
| Sector | 26 | 28 | 25 | 24 | 30 |
2021 to 2025 data
| Year | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|
| Anglian Water | 2 | 2 | 2 | no data | no data |
| Northumbrian Water | 4 | 3 | 3 | no data | no data |
| Severn Trent Water | 4 | 4 | 4 | no data | no data |
| Southern Water | 1 | 2 | 2 | no data | no data |
| South West Water | 1 | 2 | 2 | no data | no data |
| Thames Water | 2 | 2 | 2 | no data | no data |
| United Utilities | 4 | 3 | 4 | no data | no data |
| Wessex Water | 2 | 2 | 4 | no data | no data |
| Yorkshire Water | 2 | 3 | 2 | no data | no data |
| Sector | 22 | 23 | 25 | no data | no data |
Figure 1. Total EPA star ratings for the 9 water and sewerage companies 2011 to 2023 – using the methodology at the time compared to the 2023 methodology
Chart note: application of the current EPA methodology for 2023 data to previous years of data is subject to caveats due to changes in our expectations and EPA metric definitions.