Swimmers and surfers have said they are scared to go in the sea due to fears about sewage.
Ahead of the general election, activists said they wanted to see change because “people are getting ill”.
Surfers Against Sewage said it was hearing about “alleged illegal spillages” almost every day.
While sewage can be discharged by water companies in certain circumstances, pollution can also be caused by other industries such as agriculture and construction.
Langland Bay in Gower, Swansea county, attracts hundreds of swimmers and surfers, but swimming group leader Howard Jones said fewer people now wanted to take a dip.
“It’s not just Langland, Caswell, Swansea, I’m hearing of children with ear infections or stomach infections. It’s hard to pinpoint it.
“Certainly, in the last six months we’ve got more and more people complaining about this issue.”
Sally Howells, 57, Â travels from Cardiff to Gower to swim, and tracks alerts about sewage discharges.
“I’m frightened to go in to be perfectly honest,” she said. “It’s a risk to go swimming.”
Keen swimmer Rupert Miles, 62, said he thought his recent illnesses may have been linked to sea swimming.
“I’ve had a couple of bouts of rather nasty gastric flu, which I’ve been to the doctors about,” he said.
“You don’t want to point the blame, but they said ‘you sea swim, it could be sewage’.”
Caris Bowen, 32, coaches open-water swimming and prefers to teach in a spring water lake in Glynneath rather than the sea.
“I have to check an app on a daily basis to see if it’s safe for us,” she said.
“It’s got a lot worse… it’s worrying. It’s going to have a massive effect on my business.”
When rainfall is heavy, treatment plants can discharge untreated sewage to prevent the system from being overwhelmed.
However, if plants release more sewage than they are allowed to release, they could be in breach of their permits.
Natural Resources Wales (NRW), who monitors water in Wales, was asked to comment but declined.
Welsh Water, which provides services for the majority of communities in Wales, previously said the illegal discharge of untreated sewage was “inevitable” given the scale and age of its infrastructure.
The water firm said by 2025 it would have invested over £1.4bn in its wastewater system and works closely with regulators.
Many powers relating to the water industry are devolved in Wales, but Surfers Against Sewage activists said they wanted all politicians to work together.
“It’s almost a daily occurrence that we’re hearing about alleged illegal spillages,” said Alun Moseley.
“We’re hearing stories of people becoming sick.
“We’ve passed the point of hearing empty promises. We need to see change.”
Welsh Water said it took responsibility for protecting bathing waters seriously and was investing in environmental projects.
“There are a number of contributing factors that impact on bathing and river water quality more generally. These include agricultural run-off and animal faeces, urban surface water drainage and misconnected drains,” it said.
“We are committed to working closely with regulators and other sectors to ensure we do all we can to protect the environment.”
What do the parties say?
Labour insisted its government in Wales was “leading the charge” to “tackle all sources of pollution”.
“A UK Labour government will keep pushing for improvements, including by giving regulators the powers to block the payment of bonuses to executives who pollute our waterways.”
The Conservatives said the UK government was “holding water companies to task by subjecting polluters to unlimited penalties”.
“The Welsh Conservatives have long called for Labour and NRW to hold water firms to account and issue penalty fines.”
Plaid Cymru cited an “outdated sewerage network” and “lack of robust devolved powers” in Wales.
“Plaid Cymru firmly believes that the supply and treatment of water in Wales should ultimately be managed by a single publicly-owned body,” it said.
“We would also formally request powers from the UK government over the licensing of sewage in Wales.”
While the Liberal Democrats have not yet released its manifesto in Wales, the UK branch of the party say it would “strive towards protecting our rivers and coastlines”.
“It is a complete scandal that both the UK Conservative government and the Welsh Labour government have allowed water firms to get away with polluting our waterways here in Wales,” it said.
Reform UKÂ said it “would impose a proper system of regulation with very heavy fines for water companies that pollute our natural environment”.
“It is unacceptable that overseas shareholders get rich, while prices have soared, and raw sewage is pumped into our rivers and seas.”
The Green Party said it was “an utter scandal that people no longer feel safe to swim in our seas”.
“The only way to end this scandal is to bring the water companies back into public ownership.”
