More than 1,000 pollution incidents involving septic tanks or private sewage systems occurred in England over the last decade, new figures have revealed.
Septic tank and waste management specialist CSG submitted a Freedom of Information request to the Environment Agency to discover how many pollution incidents there had been involving septic tanks or private sewage systems between 2015 and 2025.
The figures revealed there were a total of 1,184 incidents across England – with 69% of cases occurring at domestic properties.
The majority of offences occurred in rural areas where septic tanks are more prevalent. According to the EA, there were 224 incidents in East Anglia alone – 19% of all incidents – including 22 in 2025.
An estimated three million UK households use cesspits or septic tanks rather than being connected to the main sewage system, usually through necessity.
CSG is one of the largest domestic waste operators, cleaning more than 20,000 septic tanks each year.
Group Operations Manager David Cashmore said: “There are millions of people across the country who rely on private sewage systems. The vast majority are maintained effectively but we wanted to find out the extent of the pollution problem.
“Faulty septic tanks can cause serious issues, including polluted streams and waterways, contamination of watercourses, bad smells and harm to fish and wildlife.
“Under Environment Agency rules, non-compliant septic tanks can lead to enforcement notices and fines so it is important owners take the issue seriously and deploy a robust maintenance strategy.”
There were 120 recorded incidents nationally in 2025 compared with just 78 in 2024 and 89 in 2023.
The worst year for pollution from septic tanks and private sewage systems was 2021, when 152 incidents were recorded, the figures revealed.
According to information obtained from the EA, the number of Land and Water Environment Officers responsible for septic tank enforcement and compliance has fallen significantly between 2014/15 to 2024/25.
While there were 303.5 full-time equivalent (FTE) officers in 2014/15, there were just 182.5 FTE officers in 2024/25.
There was just one prosecution for ‘illegal discharging by septic tanks or private sewage systems’ between 2015 and 2025. It occurred in 2019 in the Cumbria & Lancashire region.
EA rules state that septic tank owners must arrange emptying once a year or in line with the manufacturer’s instructions.
Fully licensed by the EA and British Water, CSG has a large fleet of tankers in a range of different sizes to efficiently and carefully access properties, even if in the most distant or rural locations.
The full regional and annual breakdown of EA figures
| 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | Total | ||
| Central | 1 | 1 | 2 | ||||||||||
| Cumbria and Lancashire | 9 | 3 | 4 | 9 | 8 | 3 | 7 | 2 | 5 | 6 | 1 | 57 | |
| Devon, Cornwall and the Isles of Scilly | 5 | 6 | 5 | 7 | 3 | 4 | 16 | 6 | 12 | 10 | 17 | 91 | |
| East Anglia | 17 | 12 | 12 | 25 | 26 | 27 | 25 | 21 | 18 | 19 | 22 | 224 | |
| East Midlands | 2 | 8 | 2 | 4 | 5 | 3 | 6 | 1 | 2 | 2 | 4 | 39 | |
| Gtr Mancs Mersey and Ches | 3 | 5 | 6 | 3 | 2 | 6 | 3 | 3 | 4 | 35 | |||
| Herts and North London | 6 | 8 | 6 | 6 | 5 | 13 | 2 | 3 | 1 | 3 | 53 | ||
| Kent, South London and East Sussex | 8 | 6 | 6 | 21 | 17 | 9 | 18 | 6 | 2 | 2 | 11 | 106 | |
| Lincs and Northants | 16 | 6 | 8 | 8 | 8 | 7 | 15 | 5 | 5 | 14 | 7 | 99 | |
| North East | 8 | 4 | 6 | 8 | 7 | 4 | 3 | 4 | 10 | 2 | 12 | 68 | |
| Solent and South Downs | 4 | 10 | 10 | 14 | 12 | 10 | 21 | 12 | 9 | 1 | 11 | 114 | |
| Thames | 8 | 7 | 1 | 7 | 11 | 8 | 10 | 2 | 6 | 2 | 6 | 68 | |
| Wessex | 1 | 2 | 5 | 4 | 5 | 13 | 9 | 11 | 3 | 5 | 8 | 66 | |
| West Midlands | 15 | 11 | 11 | 11 | 11 | 4 | 7 | 9 | 8 | 7 | 11 | 105 | |
| Yorkshire | 7 | 2 | 6 | 3 | 11 | 5 | 7 | 4 | 4 | 5 | 3 | 57 | |
| Grand Total | 109 | 90 | 88 | 127 | 133 | 112 | 152 | 86 | 89 | 78 | 120 | 1184 |
