Data released by the Environment Agency has revealed that sewage storm overflow discharge in England during 2024 reached record levels of 3.6 million hours.
This represents an astonishing 3,600 percent increase over the past nine years. When the Environment Agency first started recording such date in 2016, the total duration of storm overflow events was 100,533 hours.
Whilst the amount of time for which sewage was released increased from 2023, the total number of spill events decreased by 2.9 percent to 405,398 incidents.
On average, each storm overflow in England spilled 31.8 times during 2024. Down from 33.1 over the previous 12 months.
39 percent of overflows discharged fewer than 10 times, compared to 40.5 percent in 2023. 12.5 percent of overflows did not discharge any sewage in 2024, down from 13.9 percent the previous year.
The Environment Agency admitted sewage discharge figures for 2024 showed “unacceptably high” storm overflow spill counts and durations.
Environment secretary Steve Reed used much stronger language when reacting to the data, saying: “These figures are disgraceful and are a stark reminder of how years of underinvestment have led to water companies discharging unacceptable levels of sewage into our rivers, lakes and seas.”
“We’ve already placed water companies under tough special measures through the landmark Water Act, banning unfair bonuses for polluting water bosses and introducing criminal charges for lawbreakers.”
“That’s why this government has secured over £100bn of private sector investment to upgrade our crumbling infrastructure and not only clean up our rivers, lakes and seas for good, but also help deliver economic growth across the country as part of our Plan for Change,” Mr Reed added.
What is behind the alarming sewage discharge figures for 2024?
As Mr Reed alluded to, one major reason behind the number of storm overflow events taking place is infrastructure failing to keep pace.
Water utilities companies often justify their discharging of sewage into the environment through wastewater treatment plants being unable to handle a sudden surge in water levels during storms where systems combine stormwater and wastewater.
With the risk that sewage could back up into homes and streets, it is better to release sewage than see it flood homes and businesses.
Tying storm overflows to the weather, 2024 was one of the wettest years on record in England. It ranked eighth for rainfall, adding strain to sewer systems and resulting in more frequent and prolonged overflows.
Sewage discharge levels in 2024 are also far more accurate than ever before. 100 percent of storm overflows are now fitted with Event Duration Monitors (EDMs). In 2010, only seven percent of overflows were monitored.
A 93 percent increase in the number of overflows reporting figures will significantly increase the amount of data regarding spills.
What is being done about storm overflows?
The Environment Agency is taking action to try and reduce the number of storm overflows and their duration.
How much untreated wastewater can be released is governed by Storm Overflow Assessment Frameworks. These have been updated so that any spill – no matter how brief – which takes place on a day defined as being dry is categorised as a pollution incident.
There has also been an expansion of legal powers under the Water Special Measures Act, which passed into law in February 2025.
Water utilities chief executives can now be held personally liable for companies failing in their duty to prepare, publish and report on pollution incidents and reduction plans.
Performance-related pay for directors and shareholders will be more tightly linked to company performance in specific areas, such as the environment and financial resilience.
In terms of infrastructure, water utilities companies are seeking new emergency leaking wastewater pipe repair methods to reduce the amount of sewage spilled during unexpected bursts.
And the Water Industry National Environment Programme (WINEP) in England commits £10.2 billion of its £22.1 billion total funding to storm overflow improvements. This includes upgrading over 2,500 overflows and installing 3,500 new monitors.
Can sewage discharge be reduced in 2025?
Storm overflows in 2024 buckled under the pressure of climate variability, outdated infrastructure and a long-standing legacy of systemic underinvestment.
Stronger than ever monitoring should be encouraging water utility companies to clean up their act when it comes to sewage discharge.
The data recorded by the Environment Agency must start translating into cleaner rivers for communities. Getting there will require sustained enforcement of spill rules, robust investment in infrastructure and swift delivery of upgrades.
If all that starts to happen in 2025, maybe sewage discharge levels in England will start to come down. But it is a mighty-big if…
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