Thirsty wasps, discovered in the electrical boxes of two wells in Pablo, are blamed for an E. coli contamination that forced residents and businesses to boil water and consume bottled water for two weeks.

In a letter issued Dec. 4 by the Department of Environmental Quality, the Pablo Water and Sewer System was told it could end the boil-water advisory that had been issued Nov. 20 due to evidence of bacterial contamination.

According to a notice posted on the Pablo Water and Sewer website, a DEQ inspector was in Pablo on Nov. 28 to assess the water treatment facility. During his visit, wells that tested positive for e. coli “underwent a scrupulous overhaul,” revealing that wasps had infiltrated the electrical boxes of two wells.

According to the notice, the DEQ inspector “surmised that the yellow jackets has been looking for water during the dry conditions of summer and had been traveling the conduit of electrical lines to discard their dead and consume the water inside the well.”

Wasps are known to carry bacteria of Escherischia coli (e. coli) and Salmonella, both of which can cause food poisoning and gastro-enteritis.

In response, the electrical boxes were cleaned, the conduits were sealed, and the wells were flushed with chlorine for several hours. The samples taken around noon last Friday were free of contamination, and the DEQ lifted the boil order Monday.

“We were fortunate to have found the potential source of contamination,” wrote Pablo Water and Sewer Director Luke Taylor.

The water and sewer system has close to 600 connections. In addition to around 2,075 residents, it supplies water to CSKT Tribal Headquarters, Salish Kootenai College, Pablo Elementary and Two Eagle River School.