PIPES around Bencoolen Bridge, Bude are to be surveyed after consistently high levels of bacteria were found in the River Neet.
The pollution is believed to be affecting bathing water quality at nearby Summerleaze Beach.
Environment Agency scientists are to carry out a detailed survey of pipes discharging into the river around Bencoolen Bridge from the Killerton Road area of the town in an attempt to improve water quality.
The bacteria were detected when a series of samples were taken by the agency's monitoring and data team.
Its officers will be working closely with South West Water and North Cornwall District Council. They will concentrate on pipes containing the highest level of contamination in an attempt to locate the source of the pollution.
Some of the pipes draining from Killerton Road date from Victorian times and are in poor condition.
The pollution could be coming from leaks or misconnections to local surface water drains.
The agency will use hi-tech methods to pinpoint the pollution, including a spore-producing bacterium called bacillus globigii that mimics the bacteria found in sewage and enables scientists to trace the movement and distribution of potentially harmful bacteria. Colourful tracer dyes will also be used.
The agency's James Wimpress said: "We carried out a preliminary survey last month to determine which pipes discharge from Killerton Road into the River Neet. The next phase of the project is to take a closer look at the pipes around Bencoolen Bridge to try to find out the source of the bacterial contamination.
"We've already discovered that some of the pipes run close to a main sewer that might be leaking into the surface water system. There's a history of bathing water quality problems at Bude, so it is important we press ahead with this investigation."
Once the agency has completed its survey of the Killerton Road area, it may target other areas of the town.