Surfers and beach users are being urged to back an extension to the bathing season to stop raw sewage being dumped when it rains.
The number of Westcountry beaches boasting the highest water quality standards dropped to the lowest level for a decade last year because of the washout summer.
The Government has now launched a consultation as part of plans to modernise the official season, which currently runs from May 15 to September 30.
Labour says the Department for Environment, Food and Rural Affairs (Defra) is attempting to reduce the water testing, which only takes place during this time.
Campaign group Surfers Against Sewage (SAS) said there was a dramatic increase in the amount of unmonitored sewage discharged out of season.
It said the online survey was a golden opportunity to extend the period from April until October, thereby adding two months' extra water testing.
Campaign director Andy Cummins said Defra was "neutral" on the issue but many local authorities had been lobbying for a shorter season to avoid testing around the "shoulders" of the summer, when rainfall causes more sewage discharges leading to beaches failing to meet standards.
"The way people use the sea has changed dramatically in the past 40 years, with improvements to wet suits and the popularity of sports such as kite surfing," he added.
"The current testing system is quite misleading for the public who may not realise that beaches are only tested in the bathing season.
"If there is a strong representation to the survey from people who care about the environment it will be hard for the Government to ignore."
Across other Europe the season length varies, in some cases with different rules for coastal and inland waters.
Defra says the season for England's 416 designated and monitored bathing waters must be continuous but can be shorter or longer.
Depending on the outcome of the survey, an impact assessment will be prepared and a detailed consultation will be carried out during the winter.
A spokesman for the department added: "We want to make sure our bathing season coincides with when people want to enjoy bathing waters.
"That is why we are gathering views on whether the dates are still suitable and we are open to all options at this stage."
MP Mary Creagh, Labour's Shadow Environment Secretary, said: "Families packing their bags for the seaside will be horrified to hear that Ministers want to reduce checks on sewage in the sea.
"The British summer is short enough and our coastal businesses and communities are struggling."