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This publication is available at https://www.gov.uk/government/publications/water-and-sewerage-companies-in-england-environmental-performance-report-2025/yorkshire-water-epa-data-report-2025
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 and sewerage 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 and sewerage companies and wider regulatory information see the environmental performance of the water and sewerage companies in 2025 report.
We set targets for each EPA metric. Water and sewerage company performance is then given a red, amber or green (RAG) status:
red – significantly below target
amber – below target
green – achieved target
We review and revise thresholds every 5 years.
1. EPA metric status and performance star rating
Main facts
For 2025:
red status for 3 metrics, amber status for 0 metrics and green status for 3 metrics
1 of 4 water and sewerage companies (out of 9) rated as poor performing (1 stars)
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
2022
3 stars
Good company
2023
2 stars
Company requires improvement
2024
2 stars
Company requires improvement
2025
1 star
Poor performing company
Annual percentage of red, amber or green (RAG) status EPA metric results for Yorkshire Water
Graph note: there were 6 EPA metrics in the years 2011 to 2015, 2018 to 2021, and 2025. There were 7 EPA metrics in the years 2016, 2017, 2022, 2023 and 2024.
Annual number of EPA metrics and their RAG status results for Yorkshire Water
Year
Number of metrics in EPA
Number of red metrics
Number of amber metrics
Number of green metrics
2011
6
1
2
3
2012
6
1
3
2
2013
6
0
3
3
2014
6
0
1
5
2015
6
0
2
4
2016
7
0
3
4
2017
7
0
3
4
2018
6
1
3
2
2019
6
0
4
2
2020
6
0
1
5
2021
6
1
2
3
2022
7
0
2
5
2023
7
1
2
4
2024
7
2
3
2
2025
6
3
0
3
2. Total pollution incidents (sewerage) metric (category 1 to 3)
Main facts
For 2025:
50 sewerage pollution incidents per 10,000km of sewer – this is rated as red
260 actual incidents (needed 101 or fewer to be rated as green)
52,263km sewer length – from financial year ending 2018 (this baseline is used in the EPA)
performance was worse than the sector (41) for sewerage pollution incidents per 10,000km of sewer
1 of 8 water and sewerage companies (out of 9) to be rated red
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
green
amber
amber
red
Incidents per 10,000km sewer
27
22
26
29
50
Actual incident numbers
143
117
137
151
260
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 and sewerage 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 2025
Asset type
Number of pollution incidents (category 1 to 3)
Combined sewer overflow
14
Foul sewer
93
Other water industry premises
0
Pumping station
39
Rising main
22
Sewage treatment works
87
Storm tank
1
Surface water outfall
4
Water distribution system (water supply)
71
Water treatment works (water supply)
4
Note: water distribution system and water treatment works (both water supply assets) are not part of the EPA total pollution incidents (sewerage) metric.
Number of pollution incidents (total and breakdown of categories 1 to 3) from Yorkshire Water sewerage and water supply assets in 2025
Asset type
Category 1 to 3
Category 1
Category 2
Category 3
Combined sewer overflow
14
0
1
13
Foul sewer
93
0
5
88
Other water industry premises
0
0
0
0
Pumping station
39
0
1
38
Rising main
22
0
2
20
Sewage treatment works
87
0
4
83
Storm tank
1
0
0
1
Surface water outfall
4
0
0
4
Water distribution system (water supply)
71
0
0
71
Water treatment works (water supply)
4
0
0
4
3. Serious pollution incidents (sewerage and water supply) metric (category 1 and 2)
Main facts
For 2025:
13 serious incidents – this is rated as red (needed 0 to be rated as green)
13 serious incidents from sewerage assets
0 serious incidents from water supply assets
1 of 7 water and sewerage companies (out of 9) to be rated red, no water and sewerage companies rated green
Annual number of serious pollution incidents (category 1 and 2) from Yorkshire Water assets (sewerage and from 2023 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
amber
red
red
red
Serious incident numbers – all assets
5
3
5
13
13
Serious incident numbers – sewerage
5
3
5
10
13
Serious incident numbers – water supply
0
0
0
3
0
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 and sewerage company sewer length data. We review and revise thresholds every 5 years. For 2021 to 2025 water and sewerage 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 2025
Asset type
Number of serious pollution incidents (category 1 and 2)
Combined sewer overflow
1
Foul sewer
5
Other water industry premises
0
Pumping station
1
Rising main
2
Sewage treatment works
4
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 2025:
82% of all incidents self-reported, 94% from just pumping stations (PS) and sewage treatment works (STW) combined – this is rated as green
276 self-reported incidents, 59 incidents reported by others
performance was worse than the sector (87%) for self-reporting of all pollution incidents
performance was better than the sector (93%) for self-reporting of just PS and STW pollution incidents combined
1 of 8 water and sewerage companies (out of 9) 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
amber
amber
amber
green
Percentage of incidents self-reported
66
77
75
78
82
Number of incidents self-reported
107
112
130
153
276
Percentage of PS and STW incidents self-reported
74
95
88
84
94
Number of PS and STW incidents self-reported
40
37
58
71
118
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 2025
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
10
4
Foul sewer
61
32
Other water industry premises
0
0
Pumping station
36
3
Rising main
18
4
Sewage treatment works
82
5
Storm tank
1
0
Surface water outfall
3
1
Water distribution system (water supply)
61
10
Water treatment works (water supply)
4
0
Self-reporting of serious pollution incidents (category 1 to 2) from Yorkshire Water sewerage and water supply assets in 2025
Asset type
Number of serious pollution incidents self-reported (category 1 to 2)
Number of serious pollution incidents not self-reported (category 1 to 2)
Combined sewer overflow
0
1
Foul sewer
1
4
Other water industry premises
0
0
Pumping station
1
0
Rising main
2
0
Sewage treatment works
3
1
Storm tank
0
0
Surface water outfall
0
0
Water distribution system (water supply)
0
0
Water treatment works (water supply)
0
0
5. Discharge permit compliance (numeric) metric
Main facts
For 2025:
99.0% numeric discharge permit compliance – this is rated as green
22 permitted discharge outlets from water treatment works (WTW) – 100% compliance (0 non-compliant WTW)
performance was better than the sector (97.4%) for numeric discharge permit compliance
1 of 2 water and sewerage 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
green
green
amber
green
Percentage permit compliance
99.0
99.7
99.7
98.4
99.0
Number of permitted discharge outlets from STW
291
293
292
292
292
Number of permitted discharge outlets from WTW
19
19
17
19
22
Number of non-compliant STW
3
1
1
5
3
Percentage compliance STW
99.0
99.7
99.7
98.3
99.0
Number of non-compliant WTW
0
0
0
0
0
Percentage compliance WTW
100.0
100.0
100.0
100.0
100.0
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 March 2026 (cumulative progress years 1 to 5 of the WINEP):
93.2% EPA schemes completed within planned deadlines – this is rated as red (needed 100% to be rated as green)
68 EPA schemes completed within planned deadlines
5 EPA schemes did not meet requirements within planned deadlines – 5 water quality
performance was better than the sector (80.2%)
1 of 4 water and sewerage companies (out of 9) to be rated red
2 non-EPA WINEP schemes completed out of 2 planned – 100% total WINEP delivery (EPA and non-EPA schemes)
Annual delivery of the WINEP (National Environment Programme up to the financial year ending 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/WINEP 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
green
green
red
red
Percentage of WINEP complete within deadlines (to date)
100
100
100
95.6
93.2
Cumulative number of schemes completed during AMP period
157
295
368
667
68
Cumulative number of water quality schemes completed during AMP period
135
272
339
571
67
Cumulative number of water resources schemes completed during AMP period
8
9
12
64
0
Cumulative number of fisheries, biodiversity and geomorphology schemes completed during AMP period
14
14
17
32
1
Annual delivery of the WINEP (National Environment Programme up to the financial year ending 2020) by Yorkshire Water, also showing EPA status and thresholds
Table and graph 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 2025:
100% satisfactory sludge disposal and use – this is rated as green
87,330t (tonnes dry solid) total volume dispatched
16,480ha (hectares) land used by them for spreading
89.63% of sludge dispatched was used by them in agriculture
1 of 8 water and sewerage companies (out of 9) to report 100% satisfactory sludge disposal and use – all water and sewerage companies rated green
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
green
green
green
green
Percentage of sludge compliant
no data
99.91
99.84
99.67
100
Total volume of sludge dispatched (t thousands dry solid)
101.4
80.8
74.6
81.2
87.3
Table note: for the 2018 to 2021 calendar years, 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 by them in agriculture (t thousands)
Sewage sludge recovered by them non-agriculture (t thousands)
Sewage sludge disposed of by them or passed to other outlets (t thousands)
2021
74.5
26.9
0.0
2022
76.7
3.4
0.8
2023
73.5
0.8
0.3
2024
79.3
1.5
0.4
2025
78.3
7.1
2.0
8. Event Duration Monitoring (EDM) delivery
We have published the EDM storm overflow annual return dataset received from water and sewerage companies. This shows how often and how long the monitored storm overflows operated during 2025. The dataset also includes water and sewerage company reasons for performance issues with monitors and reasons for high spill counts.
Yorkshire Water storm overflows
Year
2025
Total number of active storm overflows listed in the annual return
2,184
Total number of active storm overflows with EDM commissioned
2,184
Percentage of active storm overflows listed with EDM commissioned
100%
Total number of storm overflows with spill data
2,176
Percentage of storm overflows listed with spill data
99.6%
Average number of spills per storm overflow with spill data
23.6
Average duration (hours) per monitored spill event
5.6
Percentage storm overflows with ≥90% EDM operation during reporting period
