MPs have been warned that “somebody is going to die” due to the state of England’s rivers.

Water sector leaders and rivers minister Robbie Moore were questioned by the Environmental Audit Committee during a tense session on water quality and infrastructure on Wednesday.

It followed reports earlier in the day that millions of litres of raw sewage were pumped into Lake Windermere, prompting a fresh row over the quality of England’s waters as the bathing season starts.

Customers in Devon were then told by South West Water to boil their drinking water as cases of a diarrhoea-type illness caused by the parasite cryptosporidium were confirmed.

Asked by MPs about the current state of UK rivers, Charles Watson, chairman of River Action UK, said: “The public is not safe.”

“Temperatures are warming up, it’s half-term in three weeks’ time. Tens of thousands of families are going to be in the rivers, on our beaches, going to lakes, none of which have bathing status protections,” he added.

“I’m not exaggerating, somebody is going to die because of this pathogen level. Nobody seems to be interested in it. The water companies won’t give any public health guidance on it.”

Mr Watson spoke about how River Action UK published guidance for water users ahead of the Oxbridge Boat Race in March after finding high levels of E.coli in the water.

He told the committee that “people like us” should not be having to monitor the quality of water in England’s rivers.

“Nobody else is monitoring this terrible situation,” Mr Watson added.

“This should be done by the people empowered, the Environment Agency, to protect the public.”

Dr Rob Collins, head of policy and science at the Rivers Trust, also warned MPs that the UK has “no monitoring of any pathogens directly”.

“We have monitoring of E.coli. That is just an indicator,” he said.

“Should you swallow a mouthful of norovirus, campylobacter, cryptosporidium… we have so little information on that other than a few academic studies.

“The Environment Agency don’t monitor those pathogens so that’s a critical gap in our knowledge.”

Mr Watson argued that a key issue is funding for the regulatory bodies tasked with protecting the environment and rivers.

He said that until law enforcement “is properly funded, and polluters are held to account and made to suffer real penalties”, there will be no disincentive to pollute.

Dr Collins told the committee that only 16% of English surface waters have “good” ecological status, and not a single river has “good” chemical status despite the Environment Agency aiming for 77% of water bodies to have good status by 2027.

“It feels like we’re in a pretty dire situation and it reflects years of underinvestment,” he said.

Water minister Robbie Moore was later questioned by the MPs about the 2027 target, saying that it is “absolutely” the Government’s ambition to reach a point where 75% of rivers have good ecological status.

“We have made significant improvements… to ensure that as a Government we are putting ourselves in the best position possible to meet that requirement,” he said.

In a tense exchange, Conservative MP Matthew Offord expressed frustration over hearing “minister after minister say that bathing water quality is getting better in this country, but the system that you use to test the water is in many ways redundant”.

He questioned Mr Moore about whether the Government will make changes to the system, “so that it’s fit for purpose”, such as expanding the monitoring beyond the summer bathing period.

“We are looking specifically at those reforms,” Mr Moore said, adding that good or excellent ratings of bathing water sites have improved from 76% to 90% since 2010.

Dr Offord replied: “Congratulations, you’ve just repeated everything I’ve heard in my 14 years of being a member of Parliament about bathing water quality, and you fill me with no confidence. It’s just incredible.”

Questioned about the Windermere sewage spill, Mr Moore said: “This is a completely unsatisfactory situation.”

He said an investigation is “happening as we speak”, adding that should wrongdoing be established he expects the regulators to enforce “appropriate penalties”.