Agency inspectors are investigating at farms and homes

Llangrannog beach is one of the most popular along the Cardigan bay coastline but contamination of the water has led to it falling to achieve EU mandatory standards.

Now the Environment Agency has started trying to find possible sources of pollution - particularly slurry and sewage which are contributing to high levels of bacteria on the beach.

However, local people are confident that worries over water quality will not affect tourism.

The people that come on holiday to Llangrannog come here every year and they know that the water is fit to swim in Mike Rutherford

Agency staff have visited all the farms in the Llangrannog area to find out the possible sources of slurry.

From now until March they will focus their investigation on the sewage system.

Concerns have been raised about the performance of a new waste water treatment works at Llangrannog which was set up in April.

But investigations so far suggest that the bacteria came from different sources further up the catchments and not the plant.

Paul Varallo, the agency's environment manager for Ceredigion, said it was essential that farm slurry was prevented from entering local streams draining on to the beach.

Farmers should avoid spreading slurry in wet weather, he said.

"It is in everyone's interest to ensure that bathing waters are of the highest standard and to prevent pollution entering streams" he said.

Part of the investigation will involve pouring dye down toilets

Mr Varallo added that septic tanks and cesspits were checked and emptied frequently by owners.

Mike Rutherford, landlord of The Ship pub in Llangrannog, said the poor quality of bathing water would not affect the local tourist trade.

"The people that come on holiday to Llangrannog come here every year and they know that the water is fit to swim in.

"I think the problem has risen because the beach was probably tested after high rainfall.

"Two valleys with two streams run down to the beach and a lot of rainfall will cause slurry and other waste to be carried down to the sea."

Environment Agency officers will visit houses and pour dye down toilets and sinks to check that all effluent is going to the sewage treatment plant and not entering the streams which run into the sea.

Most of the area draining to Llangrannog beach is not covered by a public sewer because the majority of properties are connected to private drainage systems.

Llangrannog county councillor Geraint Jenkins said: "The Environment Agency has to solve this problem as soon as possible, otherwise tourism could be affected next summer."