Businesses were closed and residents were advised to boil their water after E. coli bacteria contaminated a South Whidbey water system in the Bayview area.

Keith Higman, Island County’s Director of Public Health, said the bacteria were discovered Oct. 13, during a monthly test of the water system.

The source of the contaminant has not yet been determined.

“We sent one of our staff down immediately when we found out about the violation, and they conducted a survey of the water system,” Higman said.

The company that runs the system, Vistaire Water System, issued an advisory letting customers know they should boil their water before drinking it or using it for other purposes.

The notice will be in effect until the issue is resolved, Higman said.

Eliminating E. coli will require the disinfection of the the water supply, which means disinfecting the well, reservoir and the entire distribution system, Higman explained.

Vistaire is responsible for notifying its customers, not the county public health department, according to Higman.

“We only regulate systems that have less than 15 residential connections,” he said.

According to data from the state Department of Health, Vistaire Water System has 151 total connections, an estimated non-residential population of 487 and an estimated residential population of 160.

The water system covers an area ranging from Bayview Road to Crawford Road. Businesses on both sides of the highway are affected, including the Flower House Cafe, which closed during the past weekend and is following guidance to stay closed until the contamination issue is resolved.

The Goose Community Grocer closed its produce section located under a water misting system.

Vistaire Water System could not be reached for comment by press time.