Dozens of popular swimming locations in England would be deemed “poor” quality if officially designated as bathing spots, according to a report exploring the “shocking state of UK bathing waters”.

Surfers Against Sewage (SAS), which campaigns for clean oceans, rivers and lakes, released its annual water quality report on Tuesday.

The environmental group said 40 locations were sampled weekly by volunteer citizens throughout the 2023 bathing season.

It said 20 were popular sites for swimming and 20 were upstream of nearby sewage overflow associated with the swimming spots, although none of the sites are officially designated bathing waters.

The research found that 24 of these locations would be deemed “poor” quality were they designated bathing waters, as per the Environment Agency’s methodology.

The research also suggests that four out of 20 locations showed a clear decrease in water quality from locations upstream to those downstream of a sewage overflow.

SAS said the report looked at the “shocking state” of UK bathing waters in a year when untreated sewage was discharged more than 399,000 times into UK waterways – the equivalent of more than 1,000 discharge events every day.

It noted that many overflows in Scotland and Northern Ireland go unreported, meaning this figure is likely to be an underestimate of the frequency of sewage discharges into UK waters.

SAS said it also unearthed documents that indicate that Dwr Cymru Welsh Water have used emergency overflows to release sewage into designated bathing water multiple times over the last two years.

The Gwbert Emergency Overflow, which impacts the designated bathing water of Poppit Sands, discharged 24 times in the same number of months.

Elsewhere in the report, the SAS said it received 1,924 reports of cases of sicknesses due to sewage pollution in the last year, with many leading to hospitalisation, events cancelled, earnings lost and businesses closed.

Giles Bristow, chief executive of SAS, said: “Yet again, our annual water quality report reveals the complacency and disregard of governments, water companies and regulators towards the health of rivers and coastlines in the UK – and by extension people’s health.

“We are seeing failure at every level – from governments and regulators failing to enforce the law, to water company fat cats pocketing dirty money and refusing to clean up their act – with the general public ending up the biggest loser every time.

“How many times can we say ‘enough is enough’? Our leaders need to prioritise transparency, ensure laws and regulations are properly enforced, and prevent water companies profiting from pollution.”

Labour’s shadow secretary of state for the environment, Steve Reed MP, said: “The water industry is broken after 13 years of Tory government – with stinking, toxic sewage lapping up on our rivers, lakes, and seas.

“It is disgusting that families and children cannot enjoy our waters without the threat of getting sick.

“Despite this gross negligence, consumers are now expected to pay higher water bills, whilst CEOs are pocketing millions in bonuses.

“This Conservative Government is too weak to tackle this scandal. With Labour, the polluter – not the public – will pay. We will give Ofwat the powers to ban the payment of bonuses to water bosses until they have cleared up their filth.”

SAS said it has developed the End Sewage Pollution Manifesto in collaboration with environmental charities, community groups and sport governing bodies, which sets out policies to clean up UK rivers and seas.

These include enforcing the law and regulations, stopping pollution for profit, empowering a nature-led approach to tackle sewage pollution and ensuring transparency on sewage pollution.

Water minister Rebecca Pow said: “We agree the volume of pollution in our waters is utterly unacceptable, and this is the first Government in history to take such comprehensive action to tackle it.

“Our Plan for Water is delivering more investment, stronger regulation and tougher enforcement to ensure every overflow is monitored, reduce all sources of pollution and hand out swifter fines and penalties.

“This plan includes targets so strict they are leading to the largest infrastructure programme in water company history – £60 billion over 25 years – which in turn will result in hundreds of thousands fewer sewage discharges.”

A Water UK spokesperson said: “Water industry investment has transformed coastal bathing water with a sevenfold increase in the number of beaches achieving an ‘excellent’ from the Environment Agency since the 1990s.

“We now need to do the same for our rivers and inland bathing areas to ensure we meet public expectation. To do this companies are proposing to invest £11 billion over the next seven years to massively reduce storm overflows and radically improve our rivers for bathing and other recreational activities.”

Dwr Cymru Welsh Water said: “It is both misleading and disingenuous for Surfers Against Sewage to state that they have uncovered documents that identify performance issues with some of our assets as we collate this data and have made it openly available on our website for years and share with regulators and stakeholders.

“This also ignores the investment we have made to date to improve water quality in our seas and rivers, helping ensure that Wales has 25% of the UKs Blue Flag beaches while only having 15% of the coastline, and 44% of rivers achieving good ecological status compared to 14% in England.”

An Environment Agency spokesperson said: “Whether its tackling agricultural pollution, road run-off or sewage discharges, we know there is more to do to improve designated bathing sites and our waterways, which is why we will work with everyone – from farmers or water companies through to citizen scientists – to reduce pollution.

“We will also take action against polluters where there is evidence permits have not been complied with and we are conducting our largest ever criminal investigation into potential widespread non-compliance by water and sewerage companies at thousands of sewage treatment works.”