The Environment Agency says there may be contamination because of heavy rain possibly causing storm overflows to discharge untreated sewage into the water.
The notice says: ‘Pollution Risk Warning: Bathing not advised today due to the likelihood of reduced water quality.’
There is a sewer overflow from Wembury pumping station that discharges 50m upstream of the beach.
South West Water Tweeted: ‘Any discharge you can see is likely from a storm drain, these are in place to prevent the back up of sewage into homes and businesses.
Due to the dry weather water is not soaking into the ground and is going straight into the drains meaning that the overflows need to be used.’