Sligo County Council says there should be no further issues in the short term with discharges into the Easkey River in West Sligo.
Earlier this week, a Sinn Féin local election candidate in the Ballymote/Tubbercurry area claimed raw sewage was entering the river.
It was alleged the area in which raw sewage was going into the river is a public amenity used by people living in Easkey as well as by tourists.
According to Sinn Fein local election candidate Daniel Gallagher, it could be disastrous not only to the environment but also to the fishing industry in the area.
This morning, in response to a query from Ocean FM News, Sligo County Council said that on May 7th, it was notified by Inland Fisheries of a discharge into the Easkey River.
On investigation it was discovered that fats, oils and greases were causing a blockage in the network, which caused an overflow through a storm water discharge to the river.
Sligo County Council says it and Irish Water were unaware that the storm water overflow existed on the network, and are currently investigating as to the location and condition of the overflow chamber.
The council says the fats, oils and greases have been cleaned up and there should be no further issues in the short term.
The council also says it has informed Irish Water Source Control about the incident and has proposed that it contact local businesses in relation to fat, oil and grease discharges into the sewers.