The Fernwood Water and Sewer District reported Monday that up to 11,000 gallons of wastewater escaped into the St. Maries River on Thursday night.
Fernwood's pumping station No. 1 was overwhelmed due to heavy rain and melting snow, causing the release.
The district said most of the wastewater that reached the river was stormwater, and the river was at flood stage at the time, diluting the waste.
"The only good thing now is most of the snow is gone, so there is less potential" for more releases this spring, said John Sherman, an operator of the pumping station at Fernwood, which is approximately 20 miles southeast of St. Maries on Highway 3.
The district reported late last month that wastewater from the pumping station flowed into the river as well.
In a news release Monday, the district said it didn't anticipate any public health hazard as a result of the release Thursday. The river is not being used currently for "contact recreation" because of cold temperatures and high flows.
The district is in the process of correcting system deficiencies that allow the releases to occur.
Sherman said the district is considering four different options for fixing the deficiencies, and hopes to move forward to the design phase on one of the options in June.
It could cost around $500,000 or $600,000 to do the work, he said.
Following the design phase, several state and federal agencies will have to sign off on the project before work can begin, hopefully sometime in 2013, Sherman said.
He said they are doing what they can now to keep stormwater from getting into the collection system, which has weak areas, and overwhelming the pumping station.