Research and analysis

Wessex Water 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 Wessex Water’s performance across all EPA metrics

Year	Overall EPA star rating (out of 4)	Star rating description
2011	4 stars	Industry leading company
2012	4 stars	Industry leading 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	4 stars	Industry leading company
2020	4 stars	Industry leading company

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

Main facts

For 2020:

• 87 actual incidents
• 26% fewer incidents per 10,000km sewer than in 2011
• 34,551km sewer length

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	green	green	green	green	green
Incidents per 10,000km sewer	34	35	48	44	48
Actual incident numbers	58	61	83	76	83

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	green	green	green	green	green
Incidents per 10,000km sewer	22	23	24	22	25
Actual incident numbers	75	80	82	76	87

Annual number of pollution incidents (category 1 to 3) from Wessex Water 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 Wessex Water was equivalent to 87 or fewer actual incidents in 2011 to 2015, 85 or fewer in 2016 and 88 or fewer in 2017 to 2020
• red status for Wessex Water was equivalent to 224 or more actual incidents in 2011 to 2015, 166 or more in 2016 and 172 or more in 2017 to 2020

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

Asset type	Number of pollution incidents (category 1 to 3)
Combined sewer overflow	9
Foul sewer	31
Other water industry premises	0
Pumping station	8
Rising main	12
Sewage treatment works	25
Storm tank	0
Surface water outfall	2
Water distribution system (clean)*	29
Water treatment works (clean)*	4

* 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:

• 25 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:

• 4 actual serious incidents
• same number of serious incidents per 10,000km sewer as in 2011

Annual number of serious pollution incidents (category 1 and 2) from Wessex Water sewerage assets, with EPA rating

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	green	green	amber	amber	amber
Serious incidents per 10,000km sewer	1.2	0	3.5	1.7	1.7
Actual serious incident numbers	2	0	6	3	3

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	amber	amber	amber	green	amber
Serious incidents per 10,000km sewer	0.6	0.9	1.2	0.3	1.2
Actual serious incident numbers	2	3	4	1	4

Annual number of serious pollution incidents (category 1 and 2) from Wessex Water 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 Wessex Water was equivalent to 2 or fewer actual serious incidents in 2011 to 2015 and 1 or fewer in 2016 to 2020
• red status for Wessex Water was equivalent to 7 or more actual serious incidents in 2011 to 2015, 5 or more in 2016 and 6 or more in 2017 to 2020

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

Asset type	Number of serious pollution incidents (category 1 and 2)
Combined sewer overflow	2
Foul sewer	2
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:

• 1.2 serious sewerage pollution incidents per 10,000km of sewer - this is rated as amber
• performance was worse than the sector average (0.7) for sewerage pollution incidents per 10,000km of sewer
• needed 1 or fewer actual serious sewerage pollution incidents to be rated as green

4. Discharge permit compliance metric (numeric)

Main facts

For 2020:

• 299 permitted sewage treatment works (STW)
• 26 permitted water treatment works (WTW)

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	green	green	green	green	green
Percentage permit compliance	99.7	99.7	99.0	99.7	99.7
Number of permitted STW	306	304	305	301	300
Number of non-compliant STW	1	1	3	1	1

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	green	green	green	amber	green
Percentage permit compliance	99.4	99.0	100	98.5	99.1
Number of permitted STW	297	292	291	299	299
Number of permitted WTW	21	14	13	26	26
Number of non-compliant STW	2	2	0	4	1
Number of non-compliant WTW	0	1	0	1	2

Annual discharge permit compliance (numeric) for Wessex Water (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:

• 99.1% numeric discharge permit compliance - this is rated as green
• 99.7% numeric discharge permit compliance at STW and 92.3% discharge permit compliance at WTW
• performance was worse than the sector average (99.2%) for numeric discharge permit compliance

5. Self-reporting of pollution incidents metric

Main facts

For 2020:

• 85% incidents self-reported
• 102 incidents self-reported
• 18 incidents reported by others

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	amber	amber	amber	amber	green
Percentage of incidents self-reported	59	52	59	62	72
Number of incidents self-reported	38	34	53	53	75

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	green	green	amber	green	green
Percentage of incidents self-reported	76	78	74	85	85
Number of incidents self-reported	73	80	78	94	102

Annual self-reporting of pollution incidents (category 1 to 3) from Wessex Water 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 Wessex Water 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	7	2
Foul sewer	24	7
Other water industry premises	0	0
Pumping station	7	1
Rising main	12	0
Sewage treatment works	20	5
Storm tank	0	0
Surface water outfall	1	1
Water distribution system (clean)	28	1
Water treatment works (clean)	3	1

Self-reporting of serious pollution incidents (category 1 and 2) from Wessex Water 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	1	1
Foul sewer	1	1
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:

• 85% 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:

• 35 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 Wessex 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)	106	102	105	100	100
Cumulative number of schemes completed during AMP period	71	102	130	151	4

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	100	100
Cumulative number of schemes completed during AMP period	40	86	106	150	35

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:

• 44,048t (tonnes) total volume produced (dry matter)
• 10,559ha (hectares) land used for spreading
• 100% of sludge produced was used in agriculture

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	green	green	green	green	green
Percentage of sludge compliant	100	100	100	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 Wessex Water

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	69.8	4.0	0.7	74.4
2012	55.8	0.0	0.0	55.8
2013	54.3	0.0	0.0	54.3
2014	53.7	0.0	0.0	53.7
2015	52.1	0.0	0.0	52.1
2016	51.9	0.2	0.0	52.1
2017	52.8	0.0	0.0	52.8
2018	52.1	0.0	0.0	52.1
2019	51.0	0.0	0.0	51.0
2020	44.0	0.0	0.0	44.0

8. Security of Supply Index (SoSI) metric

Main facts

For the financial year ending 2021:

• 1 water resource zone
• 343 Ml/d water distributed to the network (megalitres)

Annual compliance with SoSI by Wessex Water, 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.

Wessex Water storm overflows

Year	2020
Total number of storm overflows	1,289
Number of storm overflows with annual data reported	971
Percentage of storm overflows with annual data reported	75
Average number of spills per storm overflow	30
Average duration of spill (hours)	8