FOUR North beaches are included on a blacklist of areas that face being declared unfit for bathing.
If that is the case, then the beaches - among 45 singled out along the English coastline - could be redesignated and the local authority instructed to erect signs warning that the waters were contaminated.
Peter Stevenson, Environment Agency environment management team leader for the Yorkshire coast, said it was hoped that a £55m investment in a new sewerage system in Scarborough would solve any issues there, but he said matters were not so straightforward in Staithes.
"We have done an awful lot of work in Staithes over a long, long period of time. The bathing water is inside the harbour and there is a stream also coming in," he said. "That stream brings in about 95 per cent of the bacteria in the samples we take.
"The stream is as good a quality as any fresh water course .. it's just that it comes into the harbour and there's very little dilution. It's really unfortunate geography."
Mr Stevenson said between 50 and 70 per cent of the bacteria in the stream comes from animals.
"The farming is typical of an upland hill farming area," he said. "There's no particular bad practices, or anything like that, it's just normal run off from fields of slurry or whatever.
"Even if the farmers up there adopted absolutely best practice at all times, the reduction in bacteria would not be enough to meet the minimum requirements of the new directive on a regular basis."
Local councillor John Armsby said there was no easy solution.
"The Environment Agency have said even if they spent in the region of £700,000 on tackling the farmland run-off, there's still no guarantee it would meet the new European regulations for bathing," he said.
"The latest report mentioned making large gaps in the harbour and all sort of outlandish proposals, like drilling a tunnel that diverts the whole of the water that comes down Staithes Beck to a distance away, but I don't know if they would ever get permission or if that would cure it."
In any case, Mr Stevenson said test results had been negligible.
"We produced a computer model of the harbour and the water movement within it to see if opening gaps in the harbour walls would make a difference, bearing in mind that it is there to protect both the boats and Staithes itself from the sea," he said. "Unfortunately, the results found that it made a difference, but only a very small one.
"It does look at the moment like Staithes is at risk at being poor when the new directives standards come in in 2015."