Research and analysis

Thames Water EPA data report 2019

Published 2 October 2020

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 2019 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 Thames Water’s performance across all EPA metrics

Year	Overall EPA star rating (out of 4)	Star rating description
2019	★★★☆	Good company
2018	★★★☆	Good company
2017	★★★☆	Good company
2016	★★☆☆	Company requires improvement
2015	★★★☆	Above average company
2014	★★★☆	Above average company
2013	★★☆☆	Below average company
2012	★★★☆	Above average company
2011	★★★☆	Above average company

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

Main facts

For 2019:

• 325 actual incidents
• 21% fewer incidents per 10,000km sewer than in 2011
• 109,501km sewer length

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	green	amber	amber	amber	green
Incidents per 10,000km sewer	38	68	90	76	38
Actual incident numbers	258	468	612	517	263

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	amber	amber	amber	amber	N/A
Incidents per 10,000km sewer	33	28	27	30	N/A
Actual incident numbers	357	303	297	325	N/A

Annual number of pollution incidents (category 1 to 3) from Thames 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 Thames Water was equivalent to ≤345 actual incidents in 2011 to 2015 and ≤279 in 2016 to 2019
• red status for Thames Water was equivalent to ≥885 actual incidents in 2011 to 2015, ≥542 in 2016 and ≥543 in 2017 to 2019

Number of pollution incidents (category 1 to 3) from Thames Water sewerage and clean water supply assets in 2019

Asset type	Number of pollution incidents (category 1 to 3)
Combined sewer overflow	5
Foul sewer	215
Other water industry premises	0
Pumping station	22
Rising main	18
Sewage treatment works	59
Storm tank	2
Surface water outfall	4
Water distribution system (clean) *	47
Water treatment works (clean) *	1

*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) we expect all water companies to achieve green EPA status (≤25 incidents per 10,000km sewer) by 2020.

For 2019:

• 30 sewerage pollution incidents (category 1 to 3) per 10,000km of sewer - this is rated as amber
• performance was better than the sector average (37) for sewerage pollution incidents (category 1 to 3) per 10,000km of sewer
• needed ≤279 actual sewerage pollution incidents (category 1 to 3) to be rated as green

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

Main facts

For 2019:

• 15 actual serious incidents
• 25% fewer serious incidents per 10,000km sewer than in 2011

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	amber	amber	amber	amber	amber
Serious incidents per 10,000km sewer	2.9	2.2	3.2	2.3	1.8
Actual serious incident numbers	20	15	22	16	12

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	amber	amber	amber	amber	N/A
Serious incidents per 10,000km sewer	0.9	0.9	0.8	1.4	N/A
Actual serious incident numbers	10	10	9	15	N/A

Annual number of serious pollution incidents (category 1 and 2) from Thames 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 Thames Water was equivalent to ≤10 actual serious incidents in 2011 to 2015 and ≤6 in 2016 to 2019
• red status for Thames Water was equivalent to ≥27 actual serious incidents in 2011 to 2015 and ≥16 in 2016 to 2019

Number of serious pollution incidents (category 1 and 2) from Thames Water sewerage and clean water supply assets in 2019

Asset type	Number of serious pollution incidents (category 1 and 2)
Combined sewer overflow	1
Foul sewer	3
Other water industry premises	0
Pumping station	3
Rising main	2
Sewage treatment works	4
Storm tank	0
Surface water outfall	2
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) we expect all water companies to achieve green EPA status (≤0.5 incidents per 10,000km sewer) by 2020.

For 2019:

• 1.4 serious sewerage pollution incidents (category 1 and 2) per 10,000km of sewer - this is rated as amber
• performance was worse than the sector average (0.9) for serious sewerage pollution incidents (category 1 and 2) per 10,000km of sewer
• needed ≤6 actual serious sewerage pollution incidents (category 1 and 2) to be rated as green

4. Discharge permit compliance metric

Main facts

For 2019:

• 349 permitted sewage treatment works (STW)
• 36 permitted water treatment works (WTW)

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

2011 to 2015 data

Year	2011	2012	2013	2014	2015
EPA status	green	green	red	amber	green
Percentage permit compliance	99.7	99.1	95.7	98.9	99.1
Number of permitted STW discharges	345	345	350	348	346
Number of non-compliant STW	1	3	15	4	3

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	amber	green	green	green	N/A
Percentage permit compliance	97.9	99.5	99.0	99.7	N/A
Number of permitted STW discharges	349	348	349	349	N/A
Number of permitted WTW discharges	34	35	35	36	N/A
Number of non-compliant STW	6	2	4	1	N/A
Number of non-compliant WTW	2	0	0	0	N/A

Annual discharge permit compliance (STW and from 2016 includes WTW) for Thames Water, 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 we expect all water companies to achieve green EPA status (99%) by 2020.

For 2019:

• 99.7% discharge permit compliance - this is rated as green
• 99.7% discharge permit compliance at STW and 100% discharge permit compliance at WTW
• performance was better than the sector average (98.7%) for discharge permit compliance
• best performing company for discharge permit compliance

5. Self-reporting of pollution incidents metric

Main facts

For 2019:

• 78% incidents self-reported
• 290 incidents self-reported
• 83 incidents reported by others

Annual self-reporting of pollution incidents (category 1 to 3) from Thames 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	amber
Percentage of incidents self-reported	46	50	58	53	61
Number of incidents self-reported	123	240	359	280	164

2016 to 2020 data

Year	2016	2017	2018	2019	2020
EPA status	amber	amber	green	green	N/A
Percentage of incidents self-reported	67	73	76	78	N/A
Number of incidents self-reported	244	235	254	290	N/A

Annual self-reporting of pollution incidents (category 1 to 3) from Thames 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 Thames Water sewerage and clean water supply assets in 2019

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	1	4
Foul sewer	166	49
Other water industry premises	0	0
Pumping station	15	7
Rising main	16	2
Sewage treatment works	53	6
Storm tank	1	1
Surface water outfall	1	3
Water distribution system (clean)	37	10
Water treatment works (clean)	0	1

Self-reporting of serious pollution incidents (category 1 and 2) from Thames Water sewerage and clean water supply assets in 2019

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	1
Foul sewer	2	1
Other water industry premises	0	0
Pumping station	1	2
Rising main	0	2
Sewage treatment works	2	2
Storm tank	0	0
Surface water outfall	0	2
Water distribution system (clean)	0	0
Water treatment works (clean)	0	0

For self-reporting of pollution incidents we expect all water companies to achieve green EPA status (≥75%) by 2020.

For 2019:

• 78% self-reporting of pollution incidents - this is rated as green
• performance was worse than the sector average (80%) for self-reporting of pollution incidents

6. National Environment Programme (NEP) delivery metric

Main facts

For the financial year ending 2020:

• 93 schemes were completed to the planned deadline
• 2 schemes were not completed to the planned deadline

Annual delivery of the NEP by Thames 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	amber	green	green	green
Percentage of NEP complete to date (cumulative)	109	96.8	102	102	100
Cumulative number of schemes completed during AMP period	49	60	87	130	10

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	N/A
Percentage of NEP complete to date (cumulative)	100	100	100	99.3	N/A
Cumulative number of schemes completed during AMP period	64	133	172	265	N/A

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 we expect all water companies to achieve green EPA status (≥99%) in any year.

For the financial year ending 2020:

• 99.3% NEP delivery - this is rated as green

7. Sludge disposal and use metric

Main facts

For 2019:

• 203,093t (tonnes) total volume produced (dry matter)
• 32,987ha (hectares) land used for spreading
• 79% of sludge produced was used in agriculture

Annual compliance with sludge disposal and use metric by Thames 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 Thames Water

Year	Sewage sludge used in agriculture (tonnes thousands)	Sewage sludge recovered non-agriculture (tonnes thousands)	Sewage sludge disposed (tonnes thousands)	Actual quantity produced (tonnes thousands)
2011	154.5	7.9	97.0	259.4
2012	128.5	11.9	96.0	236.4
2013	144.3	10.3	79.0	233.6
2014	170.7	14.2	72.6	257.4
2015	168.3	14.2	74.2	256.7
2016	177.8	8.6	73.5	260.0
2017	165.9	2.3	62.6	230.9
2018	173.2	3.5	45.7	222.4
2019	160.4	2.8	39.9	203.1

8. Security of Supply Index (SoSI) metric

Main facts

For the financial year ending 2020:

• 6 water resource zones
• 2602 Ml/d water distributed to the network (megalitres)

Annual compliance with SoSI by Thames Water, with EPA ratings

Financial year ending	2017	2018	2019	2020	2021
EPA status	red	amber	amber	green	N/A
SoSI score	99	97	98	100	N/A

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

For SoSI we expect all water companies to achieve green EPA status by 2020.

For the financial year ending 2020:

• 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 NEP however does not form part of the EPA NEP delivery metric.

Number of Thames Water storm overflows with EDM

Year	2019
Total number of storm overflows	472
Number of storm overflows with annual data reported	377
Percentage company coverage	80