Pembrokeshire County Council is warning people to stay away from a stream at Saundersfoot.
It follows the discovery of a sewage discharge into its water.
Warning signs and barriers have been erected and the situation is being monitored.
The discharge was discovered as a result of recent bathing water sampling by Environment Agency Wales.
The sampling showed that contamination levels were significantly higher than last year prompting an investigation by Dwr Cymru Welsh Water, Environmental Health and Environment Agency Wales officers.
An overflowing manhole has now been identified as the possible cause and plans are in place to remedy the situation.
Pembrokeshire County Council has erected warning signs and barriers to warn the public away from the stream. Sampling will continue throughout the rest of the week.
John Hogg, Environment Agency Wales, said:
“We found that recent samples taken from the local EU designated bathing water and the stream feeding it were not as good as we would have liked. In the long term, this could mean the bathing water does not achieve the highest rating for water quality.
“Investigations since then found a manhole cover, well hidden in dense undergrowth, that was overflowing. Dŵr Cymru Welsh Water and their contractors have since cleared a blockage causing the problem and are going to check the system with CCTV cameras.
“We are now testing the water daily to check that the water quality is improving.”
For further advice please contact:
Environment Agency (Wales)
08708 506506
Welsh Water
0800 0853968
Pembrokeshire County Council
01437 764551
