Research and analysis

United Utilities EPA data report 2020

Updated 14 January 2022

Applies to England

This report provides company specific data and information on the Environmental Performance Assessment (EPA) metrics. It contains current year and historic performance data. For further information on what each EPA metric means see our EPA metric guide.

In addition to the EPA metrics this report contains a section on event duration monitoring (EDM) delivery. For a comparison between water companies and wider regulatory information see the Environmental performance of the water and sewerage companies in 2020 report.

We set targets for each EPA metric. Company performance is then given a red, amber or green (RAG) status:

  • red - performance significantly below target
  • amber - performance close to or slightly below target
  • green - performance better than target

The thresholds are reviewed every 5 years.

1. EPA performance star rating

Annual performance star rating after assessment of United Utilities’ performance across all EPA metrics

Year Overall EPA star rating (out of 4) Star rating description
2011 3 stars Above average company
2012 3 stars Above average company
2013 3 stars Above average company
2014 3 stars Above average company
2015 4 stars Industry leading company
2016 4 stars Industry leading company
2017 4 stars Industry leading company
2018 3 stars Good company
2019 3 stars Good company
2020 4 stars Industry leading company

2. Total pollution incidents (sewerage) metric (category 1 to 3)

Main facts

For 2020:

  • 143 actual incidents
  • 74% fewer incidents per 10,000km sewer than in 2011
  • 74,260km sewer length

Annual number of pollution incidents (category 1 to 3) from United Utilities sewerage assets, with EPA rating

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status amber amber green green green
Incidents per 10,000km sewer 72 74 48 49 40
Actual incident numbers 315 324 208 214 175

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status green green green amber green
Incidents per 10,000km sewer 22 23 24 28 19
Actual incident numbers 172 169 181 205 143

Annual number of pollution incidents (category 1 to 3) from United Utilities sewerage assets, also showing EPA status and thresholds

Graph note: the thresholds for a RAG status are shown in the graph background. EPA thresholds for normalised incidents (per 10,000km sewer) are shown in the EPA metric guide. They are revised every 5 years. Sewer length data was collected in 2011, then reviewed and adjusted where necessary in following years. Sewer length affects the actual number of incidents required to fall within a particular RAG status:

  • green status for United Utilities was equivalent to 220 or fewer actual incidents in 2011 to 2015, 198 or fewer in 2016 and 189 or fewer in 2017 to 2020
  • red status for United Utilities was equivalent to 565 or more actual incidents in 2011 to 2015, 386 or more in 2016 and 368 or more in 2017 to 2020

Number of pollution incidents (category 1 to 3) from United Utilities sewerage and clean water supply assets in 2020

Asset type Number of pollution incidents (category 1 to 3)
Combined sewer overflow 15
Foul sewer 54
Other water industry premises 2
Pumping station 35
Rising main 6
Sewage treatment works 28
Storm tank 0
Surface water outfall 3
Water distribution system (clean)* 2
Water treatment works (clean)* 0

* Water distribution system (clean water supply) and water treatment works (clean water supply) are not part of the EPA total pollution incident (sewerage) metric.

For sewerage pollution incidents (category 1 to 3) all water companies should achieve green EPA status (for 2020 equivalent to 25 or fewer incidents per 10,000km sewer).

For 2020:

  • 19 sewerage pollution incidents per 10,000km of sewer - this is rated as green
  • performance was better than the sector average (33) for sewerage pollution incidents per 10,000km of sewer

3. Serious pollution incidents (sewerage) metric (category 1 and 2)

Main facts

For 2020:

  • 0 actual serious incidents
  • 100% fewer serious incidents per 10,000km sewer than in 2011

Annual number of serious pollution incidents (category 1 and 2) from United Utilities’ sewerage assets, with EPA rating

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status green green green green green
Serious incidents per 10,000km sewer 0.7 1.1 1.1 0.5 1.2
Actual serious incident numbers 3 5 5 2 5

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status green green green green green
Serious incidents per 10,000km sewer 0.4 0.1 0.1 0 0
Actual serious incident numbers 3 1 1 0 0

Annual number of serious pollution incidents (category 1 and 2) from United Utilities sewerage assets, also showing EPA status and thresholds

Graph note: the thresholds for a RAG status are shown in the graph background. EPA thresholds for normalised incidents (per 10,000km sewer) are shown in the EPA metric guide. They are revised every 5 years. Sewer length data was collected in 2011, then reviewed and adjusted where necessary in following years. Sewer length affects the actual number of serious incidents required to fall within a particular RAG status:

  • green status for United Utilities was equivalent to 6 or fewer actual serious incidents in 2011 to 2015 and 4 or fewer in 2016 to 2020
  • red status for United Utilities was equivalent to 18 or more actual serious incidents in 2011 to 2015, 12 or more in 2016 and 11 or more in 2017 to 2020

Number of serious pollution incidents (category 1 and 2) from United Utilities sewerage and clean water supply assets in 2020

Asset type Number of serious pollution incidents (category 1 and 2)
Combined sewer overflow 0
Foul sewer 0
Other water industry premises 0
Pumping station 0
Rising main 0
Sewage treatment works 0
Storm tank 0
Surface water outfall 0
Water distribution system (clean)* 0
Water treatment works (clean)* 0

* Water distribution system (clean) and water treatment works (clean) are not part of the EPA serious pollution incident (sewerage) metric.

For serious sewerage pollution incidents (category 1 and 2) all water companies should achieve green EPA status (for 2020 equivalent to 0.5 or fewer serious incidents per 10,000km sewer).

For 2020:

  • 0 serious sewerage pollution incidents per 10,000km of sewer - this is rated as green
  • performance was better than the sector average (0.7) for serious sewerage pollution incidents per 10,000km of sewer
  • best performing company for serious sewerage pollution incidents

4. Discharge permit compliance metric (numeric)

Main facts

For 2020:

  • 377 permitted sewage treatment works (STW)
  • 20 permitted water treatment works (WTW)

Annual discharge permit compliance (numeric) for United Utilities (STW and from 2016 includes WTW), with EPA rating

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status amber green amber amber amber
Percentage permit compliance 98.6 99.2 98.6 98.3 97.2
Number of permitted STW 360 359 359 360 358
Number of non-compliant STW 5 3 5 6 10

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status amber amber amber amber green
Percentage permit compliance 97.4 98.8 98.7 98.5 99.7
Number of permitted STW 369 374 370 372 377
Number of permitted WTW 50 30 26 20 20
Number of non-compliant STW 7 4 4 6 0
Number of non-compliant WTW 4 1 1 0 1

Annual discharge permit compliance (numeric) for United Utilities (STW and from 2016 includes WTW), also showing EPA status and thresholds

Graph note: the thresholds for a RAG status are shown in the graph background and in the EPA metric guide. They are revised every 5 years.

For discharge permit compliance (numeric) all water companies should achieve green EPA status (for 2020 equivalent to compliance at 99% or more of sites).

For 2020:

  • 99.7% numeric discharge permit compliance - this is rated as green
  • 100% numeric discharge permit compliance at STW and 95.0% discharge permit compliance at WTW
  • performance was better than the sector average (99.2%) for numeric discharge permit compliance
  • joint best performing company for numeric discharge permit compliance

5. Self-reporting of pollution incidents metric

Main facts

For 2020:

  • 82% incidents self-reported
  • 119 incidents self-reported
  • 26 incidents reported by others

Annual self-reporting of pollution incidents (category 1 to 3) from United Utilities sewerage and clean water supply assets, with EPA rating

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status green green green green green
Percentage of incidents self-reported 71 76 69 75 81
Number of incidents self-reported 229 253 155 175 163

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status green green green green green
Percentage of incidents self-reported 75 82 79 90 82
Number of incidents self-reported 144 151 154 194 119

Annual self-reporting of pollution incidents (category 1 to 3) from United Utilities sewerage and clean water supply assets), also showing EPA status and thresholds

Graph note: the thresholds for a RAG status are shown in the graph background and in the EPA metric guide. They are revised every 5 years.

Self-reporting of pollution incidents (category 1 to 3) from United Utilities sewerage and clean water supply assets in 2020

Asset type Number of pollution incidents self-reported (category 1 to 3) Number of pollution incidents not self-reported (category 1 to 3)
Combined sewer overflow 14 1
Foul sewer 37 17
Other water industry premises 1 1
Pumping station 31 4
Rising main 6 0
Sewage treatment works 28 0
Storm tank 0 0
Surface water outfall 0 3
Water distribution system (clean) 2 0
Water treatment works (clean) 0 0

Self-reporting of serious pollution incidents (category 1 and 2) from United Utilities sewerage and clean water supply assets in 2020

Asset type Number of pollution incidents self-reported (category 1 and 2) Number of pollution incidents not self-reported (category 1 and 2)
Combined sewer overflow 0 0
Foul sewer 0 0
Other water industry premises 0 0
Pumping station 0 0
Rising main 0 0
Sewage treatment works 0 0
Storm tank 0 0
Surface water outfall 0 0
Water distribution system (clean) 0 0
Water treatment works (clean) 0 0

For self-reporting of pollution incidents all water companies should achieve green EPA status (for 2020 equivalent to 75% or more of their incidents being self-reported).

For 2020:

  • 82% self-reporting of pollution incidents - this is rated as green
  • performance was better than the sector average (77%) for self-reporting of pollution incidents

6. National Environment Programme (NEP) delivery metric

Main facts

For the financial year ending 2021:

  • 5 Water Industry NEP (WINEP) schemes were completed to the planned deadline
  • 0 schemes were not completed to the planned deadline

Annual delivery of the NEP (WINEP from April 2020) by United Utilities, with EPA rating

Data for financial years ending 2012 to 2016

Financial year ending 2012 2013 2014 2015 2016
Asset Management Plan (AMP) AMP5 AMP5 AMP5 AMP5 AMP6
EPA status green green green amber green
Percentage of NEP complete to date (cumulative) 101 101 104 97 100
Cumulative number of schemes completed during AMP period 93 150 193 256 8

Data for financial years ending 2017 to 2021

Financial year ending 2017 2018 2019 2020 2021
Asset Management Plan (AMP) AMP6 AMP6 AMP6 AMP6 AMP7
EPA status green green amber green green
Percentage of NEP complete to date (cumulative) 100 100 98.6 99.7 100
Cumulative number of schemes completed during AMP period 63 106 162 290 5

Table note: AMP5 schemes that were completed early before their planned year were included in the cumulative delivery percentage (in some cases resulting in percentages over 100%). AMP6 schemes that were completed early before their planned year were not included in the cumulative delivery percentage until their planned year (cannot report over 100%). The thresholds for each RAG status are in the EPA metric guide. They are revised every 5 years.

For NEP delivery all water companies should achieve green EPA status (for the financial year ending 2021 equivalent to 99% or more of the WINEP being delivered on time).

For the financial year ending 2021:

  • 100% WINEP delivery - this is rated as green
  • joint best performing company for NEP delivery

7. Sludge disposal and use metric

Main facts

For 2020:

  • 116,750t (tonnes) total volume produced (dry matter)
  • 17,225ha (hectares) land used for spreading
  • 86% of sludge produced was used in agriculture

Annual compliance with sludge disposal and use metric by United Utilities, with EPA ratings

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status amber amber amber green green
Percentage of sludge compliant 99.1 99.2 99.9 100 100

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status green green N/A N/A N/A
Percentage of sludge compliant 100 100 N/A N/A N/A

Table note: from the 2018 calendar year, we suspended the metric from the EPA whilst we reviewed our regulatory regime for sludge. The thresholds for each RAG status are in the EPA metric guide. They are revised every 5 years.

Annual summary of sewage sludge disposal and use (dry matter) by United Utilities

Year Sewage sludge used in agriculture (t thousands) Sewage sludge recovered non-agriculture (t thousands) Sewage sludge disposed (t thousands) Actual quantity produced (t thousands)
2011 145.3 3.8 42.9 191.9
2012 112.2 3.4 30.0 145.6
2013 88.6 1.1 21.3 111.1
2014 79.4 0.9 25.8 106.1
2015 66.2 1.4 31.6 99.1
2016 67.5 4.7 26.0 98.2
2017 89.3 5.9 17.5 112.7
2018 92.7 8.3 11.1 112.1
2019 91.3 21.7 0.0 113.0
2020 100.7 16.0 0.0 116.8

8. Security of Supply Index (SoSI) metric

Main facts

For the financial year ending 2021:

  • 5 water resource zones
  • 1,853 Ml/d water distributed to the network (megalitres)

Annual compliance with SoSI by United Utilities, with EPA ratings

Financial year ending 2017 2018 2019 2020 2021
EPA status green green green green green
SoSI score 100 100 100 100 100

Table note: the thresholds for each RAG status are in the EPA metric guide.

For SoSI all water companies should achieve green EPA status (for the financial year ending 2021 equivalent to a SoSI of 100).

For the financial year ending 2021:

  • score 100 - this is rated as green

9. Event Duration Monitoring (EDM) delivery

All water companies have investment in place to monitor the vast majority of storm overflows. Installation of EDM monitors is mostly funded through the WINEP however does not form part of the EPA WINEP delivery metric. We have published the EDM dataset from the water companies describing how often and for how long the monitored storm overflows operated during 2020. All water companies have also published their EDM data returns and supporting commentaries.

United Utilities storm overflows

Year 2020
Total number of storm overflows 2,273
Number of storm overflows with annual data reported 1,925
Percentage of storm overflows with annual data reported 85
Average number of spills per storm overflow 59
Average duration of spill (hours) 6