The return of heavy rainfall in parts of the UK has overwhelmed the sewage system – meaning untreated wastewater is being released into the sea.
Pollution warnings are in place at more than 40 beaches and swimming spots in England and Wales after downpours followed months of little or no rain.
The south west and south coast of England were the worst affected, according to environmental campaign group Surfers Against Sewage (SAS), based on official data from water companies.
Water companies are already facing increased scrutiny during a period of drought and with some areas of the country facing hosepipe bans. Last month, The Times reported the country’s nine water companies are leaking almost 2.4 billion litres of water every day, while still rewarding chief executives large bonuses.
There has been growing public outrage in recent years at the volume of raw or partially-treated sewage pumped into the UK’s rivers and coastal waters.
The government faced a backlash last year over new post-Brexit legislation governing water quality. Ministers were forced to U-turn after rejecting an amendment to the Environment Bill which would force water companies to stop allowing untreated sewage to enter British waterways, saying it wanted a “progressive reduction” in the practice that has been happening for decades.
Water companies are permitted to discharge untreated sewage into rivers in exceptional circumstances, such as during heavy rainfall.
The return of downpours on Tuesday put pressure on the sewage system because the dry ground is unable to absorb the water as quickly. This also explains why flash floods have been witnessed across the country in the last two days.
Storm overflows are used to protect homes and businesses from flooding, and the water companies say only a small percentage of the discharge is wastewater.
Swimmers are advised against bathing at seven beaches in Cornwall as a result of storm sewage overflows, with four in Devon and five in Dorset also polluted by the recent downpours.
Nine beaches in Sussex, three on the Isle of Wight and three in Essex were also hit by storm sewage.
Elsewhere, there were warnings in place at spots in Lincolnshire, Cumbria, Lancashire and South Wales, as well as two inland wild swimming spots near Bristol and near Minehead in Somerset.
On Tuesday, there was an alert at Spittal near Berwick in Northumberland, although this has since cleared.
Hugo Tagholm, the chief executive of SAS, tweeted on Tuesday: “The shitstorm after the calm. Many south coast beaches off limits due to @SouthernWater sewage discharges.”
A spokesperson for SAS said there were a further nine pollution warnings in place not linked to heavy rain, and those visiting the coast are advised to always check its interactive map on its website before they swim.
In a report published in July, the Environment Agency said water company bosses should face jail for the worst pollution incidents, describing the sector’s performance in 2021 as the “worst we have seen for years”.
An Environment Agency spokesperson said on Wednesday: “The current risk of surface water flooding reinforces the need for robust action from water companies to reduce discharges from storm overflows. We are monitoring the current situation and supporting local authorities where needed.”
A spokesperson for Southern Water said: “Yesterday’s thunder storms brought heavy rain which fell on to parched ground and couldn’t absorb surface run-off, meaning that more rain than usual overwhelmed our network.
“This led to some overflows – which are used to protect homes, schools, businesses and hospitals from flooding – spilling excess water into the sea in parts of west Sussex, including Seaford.
“These discharges are heavily diluted and typically 95 per cent of them are rainwater.”
He continued: “We are dedicated to significantly reducing storm overflows and are running innovative pilot schemes across the region to reduce the amount of rainfall entering our combined sewers by 2030.”
The spokesman said a viral video of raw sewage apparently being pumped into the water at Seaford, East Sussex, was in fact surface water run-off.
Northumbrian Water said: “During the heavy rain earlier this week, a short discharge of storm water was made from a storm overflow at Spittal, near Berwick. Such discharges are mostly rainwater with a small percentage of wastewater that have come together because they use the same sewer network.
“At times of heavy rainfall, all water companies use storm overflows as a relief valve on our sewer network to protect the homes of customers and the environment from sewer flooding. Such discharges happen with both permission and scrutiny from the Environment Agency.
“In the last Bathing Water classifications released by Defra, 32 of the North East’s 34 designated bathing waters achieved either ‘excellent’ or ‘good’ ratings, with Spittal in the highest category.
“We have invested heavily in upgrades to our wastewater network in the last two decades and beyond, which have played an important part in these results, and we continue to do so. More than £80 million of investment is targeted towards improvements related to storm overflows in our current 2020-25 operating period.”
Anglian Water, which supplies Lincolnshire and also provides waste water services at Southend, said: “Combined storm overflows (CSOs) were originally designed to protect homes and businesses from flooding during heavy rainfall, like we saw last night.
“In parts of our region last night, we saw almost 100ml of rain fall in only a few hours. That’s the equivalent of well over a month’s worth on to ground that is essentially like concrete.
“As it’s been dry for so long, intense rainfall on to hard ground will not soak in and instead runs straight off.”
A spokeswoman said any discharges would predominantly have been rainwater, adding its BeachAware system had notified SAS of the discharge “as a precaution so people can make educated decisions about swimming in the sea”.
She added: “However, we recognise that they are no longer the right solution when sewers become overloaded with rainwater.
“We’ve been dealing with CSOs for years, tackling those which pose an environmental risk and working through the rest.
“Between 2020 and 2025, we’re investing more than £200 million to reduce storm spills across the East of England and, as part of our Get River Positive commitment, we’ve promised that storm overflows will not be the reason for unhealthy rivers in our region by 2030.”
Other water companies in areas where there are sewage alerts have been approached for comment.
With reporting from the Press Association.