Research and analysis

Yorkshire Water EPA data report 2021

Updated 22 July 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 (as published at the time, based on data provided in part by the water companies). For further information on what each EPA metric and performance star ratings mean see our EPA metric guide.

In addition to the EPA metrics, this report contains a section on event duration monitoring (EDM) of storm overflows. For a comparison between water companies and wider regulatory information see the Environmental performance of the water and sewerage companies in 2021 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 below target
  • green - performance better than target

We review and revise thresholds every 5 years.

1. EPA performance star rating

Annual performance star rating after assessment of Yorkshire Water’s performance across all EPA metrics

Year Overall EPA star rating (out of 4) Star rating description
2011 2 stars Below average company
2012 2 stars Below average company
2013 3 stars Above average company
2014 4 stars Industry leading company
2015 3 stars Above average company
2016 3 stars Good company
2017 3 stars Good company
2018 2 stars Company requires improvement
2019 3 stars Good company
2020 4 stars Industry leading company
2021 2 stars Company requires improvement

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

Main facts

For 2021:

  • 27 sewerage pollution incidents per 10,000km of sewer – this is rated as amber
  • 143 actual incidents (needed 122 or fewer to be rated as green)
  • 52,263km sewer length
  • performance was better than the sector average (32) for sewerage pollution incidents per 10,000km of sewer
  • 1 of 5 companies (out of 9) not to be rated green

Annual number of pollution incidents (category 1 to 3) from Yorkshire Water sewerage assets, with EPA status

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status amber amber amber amber amber
Incidents per 10,000km sewer 94 83 78 59 72
Actual incident numbers 289 253 239 180 219

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status amber amber amber amber green
Incidents per 10,000km sewer 46 43 44 35 24
Actual incident numbers 240 225 229 181 125

2021 to 2025 data

Year 2021 2022 2023 2024 2025
EPA status amber no data no data no data no data
Incidents per 10,000km sewer 27 no data no data no data no data
Actual incident numbers 143 no data no data no data no data

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

Graph note: the EPA RAG status thresholds are set for normalised (per 10,000km sewer) numbers of sewerage incidents (see our EPA metric guide). We review and revise thresholds every 5 years. Equivalent thresholds for actual incident numbers are calculated using water company sewer length data – these are shown in the graph background and the table below.

EPA thresholds for actual number of Yorkshire Water sewerage incidents for the calendar years 2011 to 2025

Calendar year Red status Amber status Green status
2011 to 2015 397 or above 155 to 396 154 or below
2016 to 2020 258 or above 133 to 257 132 or below
2021 217 or above 123 to 217 122 or below
2022 207 or above 118 to 206 117 or below
2023 196 or above 113 to 196 112 or below
2024 191 or above 108 to 190 107 or below
2025 181 or above 102 to 180 101 or below

Number of pollution incidents (category 1 to 3) from Yorkshire Water sewerage and water supply assets in 2021

Asset type Number of pollution incidents (category 1 to 3)
Combined sewer overflow 21
Foul sewer 50
Other water industry premises 0
Pumping station 21
Rising main 16
Sewage treatment works 33
Storm tank 1
Surface water outfall 1
Water distribution system (water supply) 17
Water treatment works (water supply) 1

Note: water distribution system and water treatment works (both water supply assets) are not part of the EPA total pollution incidents (sewerage) metric.

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

Main facts

For 2021:

  • 5 serious incidents - this is rated as red (needed 1 or 0 to be rated as green)
  • 5 serious incidents from sewerage assets
  • 0 serious incidents from water supply assets
  • 1 of 6 companies (out of 9) to be rated red

Annual number of serious pollution incidents (category 1 and 2) from Yorkshire Water assets (sewerage and from 2021 including water supply), with EPA status

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status red amber amber green amber
Serious incidents per 10,000km sewer 4.2 1.6 3.3 1.3 1.6
Actual serious incident numbers - sewerage 13 5 10 4 5

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status amber amber red amber amber
Serious incidents per 10,000km sewer 1.2 0.8 2.3 1.3 0.6
Actual serious incident numbers - sewerage 6 4 12 7 3

2021 to 2025 data

Year 2021 2022 2023 2024 2025
EPA status red no data no data no data no data
Serious incident numbers - all assets 5 no data no data no data no data
Serious incident numbers - sewerage 5 no data no data no data no data
Serious incident numbers - water supply 0 no data no data no data no data

Annual number of serious pollution incidents (category 1 and 2) from Yorkshire Water assets (sewerage and from 2021 including water supply), also showing EPA status and thresholds

Graph note: for 2011 to 2020 EPA RAG status thresholds were set for normalised (per 10,000km sewer) numbers of serious sewerage incidents (see our EPA metric guide). Equivalent thresholds for actual serious sewerage incident numbers were calculated using water company sewer length data. We review and revise thresholds every 5 years. For 2021 to 2025 water companies are in one of two groups with different thresholds set for actual serious sewerage and water supply incident numbers. The thresholds for actual serious incident numbers are shown in the graph background and the table below.

EPA thresholds for number of serious incidents from Yorkshire Water assets (sewerage and from 2021 including water supply) for the calendar years 2011 to 2025

Calendar year Red status Amber status Green status
2011 to 2015 13 or above 5 to 12 4 or below
2016 to 2020 8 or above 3 to 7 2 or below
2021 and 2022 4 or above 2 or 3 1 or 0
2023 and 2024 3 or above 2 1 or 0
2025 2 or above 1 0

Number of serious pollution incidents (category 1 and 2) from Yorkshire Water sewerage and water supply assets in 2021

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 2
Rising main 2
Sewage treatment works 1
Storm tank 0
Surface water outfall 0
Water distribution system (water supply) 0
Water treatment works (water supply) 0

4. Self-reporting of pollution incidents (sewerage and water supply) metric

Main facts

For 2021:

  • 66% of all incidents self-reported, 74% from just pumping stations (PS) and sewage treatment works (STW) combined – this is rated as amber
  • 107 self-reported incidents, 54 incidents reported by others
  • needed 80% or higher self-reporting and 90% from just PS and STW combined to be rated as green
  • performance was worse than the sector average (77%) for self-reporting of all pollution incidents
  • performance was worse than the sector average (88%) for self-reporting of just PS and STW pollution incidents combined
  • 1 of 5 companies (out of 9) not to be rated green

Annual self-reporting of pollution incidents (category 1 to 3) from Yorkshire Water sewerage and 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 75 78 80 77 76
Number of incidents self-reported 233 205 204 151 181

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status green green amber amber green
Percentage of incidents self-reported 79 83 73 73 81
Number of incidents self-reported 208 213 191 152 123

2021 to 2025 data

Year 2021 2022 2023 2024 2025
EPA status amber no data no data no data no data
Percentage of incidents self-reported 66 no data no data no data no data
Number of incidents self-reported 107 no data no data no data no data
Percentage of PS and STW incidents self-reported 74 no data no data no data no data
Number of PS and STW incidents self-reported 40 no data no data no data no data

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

Graph note: the EPA RAG status thresholds (for all sewerage and water supply assets) are shown in the graph background and in the EPA metric guide. We review and revise thresholds every 5 years. From 2021 the additional number in brackets is the self-reporting percentage for just PS and STW incidents combined. To achieve green status self-reporting for all assets must be 80% or above and for just STW and PS combined must be 90% or above.

Self-reporting of pollution incidents (category 1 to 3) from Yorkshire Water sewerage and water supply assets in 2021

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 15 6
Foul sewer 32 18
Other water industry premises 0 0
Pumping station 17 4
Rising main 8 8
Sewage treatment works 23 10
Storm tank 0 1
Surface water outfall 0 1
Water distribution system (water supply) 11 6
Water treatment works (water supply) 1 0

5. Discharge permit compliance (numeric) metric

Main facts

For 2021:

  • 99.0% numeric discharge permit compliance - this is rated as green
  • 291 permitted discharge outlets from STW – 99.0% compliance (3 non-compliant STW)
  • 19 permitted discharge outlets from water treatment works (WTW) – 100% compliance (0 non-compliant WTW)
  • needed 3 or fewer non-compliant treatment works to be rated as green
  • performance was better than the sector average (98.7%) for numeric discharge permit compliance
  • 1 of 5 companies (out of 9) to be rated green

Annual discharge permit compliance (numeric) for Yorkshire Water (STW and from 2016 includes WTW), with EPA status

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status amber red amber green green
Percentage permit compliance 97.3 95.2 98.0 99.3 99.3
Number of permitted discharge outlets from STW 295 294 297 299 295
Number of non-compliant STW 8 14 6 2 2

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status amber amber amber amber green
Percentage permit compliance 97.2 97.8 97.5 97.5 99.0
Number of permitted discharge outlets from STW 298 293 293 294 293
Number of permitted discharge outlets from WTW 20 21 21 22 19
Number of non-compliant STW 7 7 7 5 3
Number of non-compliant WTW 2 0 1 3 0

2021 to 2025 data

Year 2021 2022 2023 2024 2025
EPA status green no data no data no data no data
Percentage permit compliance 99.0 no data no data no data no data
Number of permitted discharge outlets from STW 291 no data no data no data no data
Number of permitted discharge outlets from WTW 19 no data no data no data no data
Number of non-compliant STW 3 no data no data no data no data
Number of non-compliant WTW 0 no data no data no data no data

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

Graph note: the EPA RAG status thresholds are shown in the graph background and in the EPA metric guide. We review and revise thresholds every 5 years.

6. Delivery of the Water Industry National Environment Programme (WINEP) metric

Main facts

For the financial year ending 2022 (cumulative year 1 and year 2 of the WINEP):

  • 100% schemes completed within planned deadlines - this is rated as green
  • 157 schemes completed (all completed within planned deadlines)
  • performance was better than the sector average (99.5%)
  • 1 of 6 companies (out of 9) to be rated green

Annual delivery of the NEP (WINEP from April 2020) by Yorkshire Water, 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 green green
Percentage of NEP complete to date (cumulative) 100 130 132 100 100
Cumulative number of schemes completed during AMP period 46 83 98 109 1

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 green green green
Percentage of NEP complete to date (cumulative) 100 100 100 99.2 100
Cumulative number of schemes completed during AMP period 34 99 144 242 11

Data for financial years ending 2022 to 2026

Financial year ending 2022 2023 2024 2025 2026
Asset Management Plan (AMP) AMP7 AMP7 AMP7 AMP7 AMP8
EPA status green no data no data no data no data
Percentage of WINEP complete within deadlines (to date) 100 no data no data no data no data
Cumulative number of schemes completed during AMP period 157 no data no data no data no data
Cumulative number of water quality schemes completed during AMP period 135 no data no data no data no data
Cumulative number of water resources schemes completed during AMP period 8 no data no data no data no data
Cumulative number of fisheries, biodiversity and geomorphology schemes completed during AMP period 14 no data no data no data no data

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 and AMP7 schemes that were completed early before their planned year are not included in the cumulative delivery percentage until their planned year (cannot report over 100%). The EPA RAG status thresholds are in the EPA metric guide. We review and revise thresholds every 5 years.

7. Sludge disposal and use metric

Main facts

For 2021:

  • 101,421t (tonnes dry solid) total volume dispatched
  • 15,240ha (hectares) land used for spreading
  • 74% of sludge produced was used in agriculture

Annual compliance with sludge disposal and use metric by Yorkshire Water, with EPA ratings

2011 to 2015 data

Year 2011 2012 2013 2014 2015
EPA status green amber green green green
Percentage of sludge compliant 100 99.7 100 100 100
Total volume of sludge dispatched (t thousands dry solid) 169.1 114.9 166.0 120.3 127.3

2016 to 2020 data

Year 2016 2017 2018 2019 2020
EPA status green green no data no data no data
Percentage of sludge compliant 100 100 no data no data no data
Total volume of sludge dispatched (t thousands dry solid) 132.3 103.9 106.9 75.8 77.0

2021 to 2025 data

Year 2021 2022 2023 2024 2025
EPA status no data no data no data no data no data
Percentage of sludge compliant no data no data no data no data no data
Total volume of sludge dispatched (t thousands dry solid) 101.4 no data no data no data no data

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

Annual summary of sewage sludge disposal and use (dry matter) by Yorkshire Water

Year Sewage sludge used in agriculture (t thousands) Sewage sludge recovered non-agriculture (t thousands) Sewage sludge disposed (t thousands)
2021 74.5 26.9 0.0

8. Supply Demand Balance Index (SDBI) metric

Main facts

For the financial year ending 2022:

  • SDBI of 100 – this is rated as green
  • 2 water resource zones
  • 1,275 megalitres per day water distributed to the network
  • 1 of 7 companies (out of 9) to be rated green

Annual compliance with SDBI by Yorkshire Water, with EPA ratings

Financial year ending 2022 2023 2024 2025 2026
EPA status green no data no data no data no data
SDBI score 100 no data no data no data no data

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

9. Event Duration Monitoring (EDM) delivery

All water companies have investment in place to monitor all storm overflows by December 2023. We have published the EDM storm overflow annual return dataset received from water companies. This shows how often and how long the monitored storm overflows operated during 2021. The 2021 dataset also includes water company reasons for performance issues with monitors and reasons for high spill counts.

Yorkshire Water storm overflows

Year 2021
Total number of storm overflows listed in the annual return 2,246
Total number of storm overflows with EDM commissioned 2,178
Percentage of storm overflows listed with EDM commissioned 97.0
Total number of storm overflows with spill data 2,087
Percentage of storm overflows listed with spill data 92.9
Average number of spills per storm overflow with spill data 33.6
Average duration (hours) per monitored spill event 5.8