Storm overflows spilled sewage into England’s rivers, lakes and coasts for new highs of more than 3.61 million hours in 2024, Environment Agency figures have shown.

It is only the second year that 100% of storm overflows have been monitored, allowing direct comparison between years, and it reveals that although the number of spills fell slightly compared with 2023, the duration of sewage discharges was up.

There were 450,398 recorded spills – which should only take place in “exceptional circumstances” to prevent sewers being overwhelmed in heavy rainfall and backing up into homes – in 2024, compared with 464,056 in 2023.

But storm overflows let sewage spill for 3,614,428 hours in 2024, slightly up on 2023’s 3,606,170 hours, and a record high.

The latest figures were branded as “disgraceful” by Environment Secretary Steve Reed, and a “stark reminder of how years of under-investment have led to water companies discharging unacceptable levels of sewage into our rivers, lakes and seas”.

Mr Reed pointed to “tough special measures” the Government had put on water companies, and said more than £100 billion in private funding had been secured for the next five years to invest in the water system.

But with high public anger over the polluted and degraded state of England’s rivers, lakes and seas, and significant bill rises coming next month to pay for the investment, campaigners and opposition politicians called for wholesale reform of the water sector and its regulators.

A spokesperson for industry body Water UK described the results as “disappointing”, but said: “We are starting to see the effect of investment with many companies reducing the number of spills in their area, despite 2024 being one of the wettest years on record.

“From April water companies will invest £12 billion to almost halve spills from storm overflows by 2030.

“This is part of the largest amount of money ever spent on the natural environment to help support economic growth, build more homes, secure our water supplies and end sewage entering our rivers and seas.”

But Giles Bristow, chief executive at Surfers Against Sewage said: “Without transformational change of the industry, how can we trust that any investment is going to improve water quality? How do we know that we aren’t still going to be swimming in sewage in 2040?”

He said the level of pollution is “not normal, it’s a disgrace” and said: “We demand radical reform, we demand an end to profit from pollution and we demand that the government listens to the voices of water users, who are absolutely sick of paying their bills only to risk getting sick themselves.”

Conservation charity River Action’s chief executive James Wallace described the numbers as “staggering”, saying they equated to 412 years of sewage polluting the country’s rivers, lakes and seas.

“Rather than fixing leaky pipes and investing in infrastructure, these companies have treated our rivers and coastlines like an open sewer and regulators have let them get away with it,” he said, calling for “real reform” of the sector.

And Liberal Democrat leader Sir Ed Davey said the figures had to be the “final nail in the coffin” for water regulator Ofwat.

“The Government should act now to get a new regulator in place to protect British rivers and seas from being pumped with disgusting sewage. It’s time for Ofwat to go,” he said.

And public ownership campaign group We Own It’s lead campaigner Matthew Topham said the state of the water sector was the “catastrophic failure” of privatisation.

“The obvious solution is to bring water back into public ownership. Profits can be reinvested to tackle the sewage crisis and lower bills,” he argued.

The figures from the Environment Agency show a slight reduction in the average number of spills per overflow, at 31.8 compared with 33.1 in 2023, while 39% of storm overflows spilled less than 10 times in the year, around the same proportion as previous years.

Meanwhile, just one in eight (12.5%) of storm overflows did not spill at all in 2024, compared with 13.9% in 2023.

England saw its eighth wettest year on record in 2024, coming after a very wet 2023, which was the fourth wettest in records dating back to the 19th century.

The Environment Agency said £10.2 billion of water company investment would be used to improve storm overflows in England in the next five years, including upgrading 2,500 outlets which is expected cut 85,000 spills a year.

And water companies will also install 3,500 monitors at emergency overflows – which are permitted to discharge raw sewage only as a last resort from the network in the event of issues such as power outages or pump failures – to protect thousands of miles of rivers.