After a decline of more than 30 years, the water quality in the Lakes of Killarney is at last showing some signs of improvement.
Recent examination of farms in the catchment area have shown better practices with regard to slurry storage and seepage into streams.
Studies have consistently shown that agricultural activities around Killarney are the main source of the enrichment of the lakes. Bylaws on slurry storage and spreading have yet to be adopted by the county council.
However, senior engineer Fergus Dillon said latest examinations showed farming practices were improving.
Fats and oils and detergents from the town's tourist industry, which services more than 1.5 million visitors annually, have also been found responsible for the pollution of the jewel in the crown of tourism, the Lower Lake.
Some of the bigger bed and breakfast houses were not linked to public sewers and their septic tanks are to be examined to see if their performance could be improved, Mr Dillon said.
Several village sewerage schemes remain to be completed. Two of the most urgent, Barraduff and Kilcummin, where a large number of houses are being built, are due to start in 2006.
Other studies have shown that principal tourist attractions themselves have inadequate sewerage systems.
A recent management plan on the national park says that Muckross House, in the heart of Killarney National Park, receives about 200,000 visitors a year, but the treatment of effluent from the house which empties into Lough Lein needs to be improved.