Endurance swimmer Joan Fennelly is undaunted by frigid water and long distances, swimming year-round in the wild. But she takes extra precautions in her own backyard. The River Thames is one of Britain's many waterways contaminated with sewage and agricultural pollution.

“If it looks right, if its smells right, I’ll go in," Fennelly said.

Britain has become notorious as a place where a casual swim could lead to an extended visit to the toilet, if not the hospital. A torrent of news on dirty water has spilled into next month's election to determine which party controls government for the next four or five years.

While not a top campaign issue, it stinks of a larger problem: Britain's aging infrastructure — from aging schools, hospitals and prisons to pothole-riddled streets.

Bad water is decades in the making, tied to the privatization of waterworks under Prime Minister Margaret Thatcher’s Conservative government in 1989 and to fiscal austerity after the 2008 financial crisis that slashed budgets for watchdogs and others.

The British public discovered the extent of the mess during the COVID-19 pandemic as outdoor recreation such as canoeing and wild swimming took off. The sight and smell of feces, toilet paper and other waste in streams and on beaches led to an outcry, along with clean water campaigns by some London newspapers.

“We are suffering with shockingly poor infrastructure as a consequence of long-term underinvestment by water utilities who appeared more interested in paying shareholder dividends,” said Nick Kirsop-Taylor, an environmental policy lecturer at the University of Exeter. “There’s far more to it than just that, though … it’s the culture of poor regulation.”

Britain had such an anti-regulatory culture on the environment that it was known as the “the dirty man of Europe” in the 1970s and 1980s, Kirsop-Taylor said. That changed when it joined the European Union, but he said there has been backsliding since its vote in 2016 to leave the EU.

While private companies have run regional monopolies providing combined water and sewage service, the population has swelled and industrial demand on the system has increased. Plumbing — dating to the Victorian era in many places — has not been updated to meet needs.

On top of that, climate change has brought heavier rainfall to overburdened sewers.

“The water companies have a choice: they either allow sewage to back up into people’s homes or they open the pipes and it flows out into nature,” said Charles Watson, founder and chair of River Action, founded in 2021. “That is why our rivers are full of human excrement.”

The number of untreated sewage discharges increased by more than 50% last year from the previous one to a record 464,000 spills. The cumulative duration of the spills doubled to 3.6 million hours, according to the Environment Agency, one of the two water regulators.

The increase was largely due to a wetter year and because monitors have now been installed on most sewage outflow pipes, according to Water UK, a trade group for water companies. But there's no similar monitoring for farm runoff like manure, an even bigger problem than sewage.

While sewage releases are legal during periods of rain, their frequency has drawn scrutiny and led to criticism that the industry’s financial regulator, Ofwat, has not done enough to ensure infrastructure is updated.

Water companies accuse Ofwat of not allowing them raise rates enough to finance improvements. Ofwat would not comment on specific criticism because of the pending election but noted that companies had underspent their budgets for improvements by 25% since 2020.

Water companies have felt the pressure. Water UK apologized last year for sewage releases, with CEO David Henderson saying the industry should have woken up sooner.

“We recognize the current levels of sewage spills are unacceptable and have a plan to sort it out," Water UK said in a statement to The Associated Press. "Companies want to invest more than 10 billion pounds ($12.7 billion) to reduce spills by 40% by the end of this decade. We now need Ofwat to give us the green light so we can get on with it.”

Activists accuse the companies of paying dividends to shareholders while running up large debts. Watson with River Action said the industry paid 11 million pounds ($14 million) last year for environmental violations such as dumping sewage while paying more than 100 times that in dividends — 1.4 billion pounds ($1.8 billion).

“That is not a deterrent,” Watson said. “That is an incentive to pollute.”

A bipartisan committee in the House of Lords last year found the two regulators needed to go further in fining and prosecuting polluters and needed more government funding. The Environment Agency's number of prosecutions has declined significantly over the years, from 787 cases in 2007-2008 to 17 in 2020-2021.

The Industry and Regulators Committee also said Ofwat had prioritized lower water bills for customers over infrastructure improvements.

Political parties are capitalizing on the crisis with tough talk. Labour leader Keir Starmer has accused the Conservative government of “turning Britain’s waterways into an open sewer.”

But neither Conservatives nor left-of-center Labour has offered much of a detailed plan. Like most other parties, they have not promised to increase regulator funding.

The leader of the centrist Liberal Democrats, Ed Davey, has made the biggest campaign splash, plunging into water for the cameras.

“The Conservatives have allowed the water companies to pump their filthy sewage into our rivers, into our lakes, onto our beaches and into our sea,” Davey said as he announced a detailed plan that includes replacing Ofwat with a tougher new regulator.

The Green Party, which struggles in a political system that makes it hard for small parties to win seats in Parliament, has even suggested that water services be nationalized again.

Some communities agree. The town council in Henley-on-Thames, in a Conservative bastion west of London, this month cast votes of no confidence in Thames Water, which is on the brink of insolvency, and called for its water provider to be nationalized.

The town is the site of the Henley Royal Regatta that draws 50,000 people a day for rowing races in July. But dirty water has tarnished its image. The center of town is downstream from a Thames Water sewage treatment plant, which the company says it plans to upgrade by the end of 2026.

“I wouldn’t swim that stretch for love nor money,” said endurance swimmer Fennelly, who suspects she got a nasty E. coli infection once there.

She and other members of the Henley Mermaids, a group of wild swimmers, now consult the Thames Water phone app that shows sewage releases. They also do the sniff test before jumping in.

On a recent morning, Fennelly and Jo Robb walked across a pasture, tied floating devices around their waists and climbed down to the Thames. The current was strong from rain the night before.

Robb screamed as she hit the river, not because it was dirty, but because of the chill. It was refreshing — the way water should be.

Susan Barry, member of the open water swimming group Henley Mermaids, swims in the river Thames, in Henley-on-Thames, England, Friday, June 14, 2024. Britain has become notorious as a place where a casual swim could lead to an extended visit to the toilet, if not the hospital. A torrent of news on dirty water has spilled into next month's election to determine which party controls government for the next four or five years. (AP Photo/Alberto Pezzali)

Bather, beware: British beaches and rivers have a sewage problem. It has seeped into election talk