Columbia Falls Removes Municipal Well from Service Following ‘Forever Chemical’ Detection

The city of Columbia Falls removed one of its three municipal wells from normal service after recent laboratory testing detected perfluorooctanoic acid (PFOA) — one of thousands of per- and polyfluoroalkyl substances (PFAS), or “forever chemicals.” 

Two separate samplings — one in June and confirmation tests in September — detected the PFAS chemical at the affected well at levels nearly double the Environmental Protection Agency’s Maximum Contaminant Level (MCL) for PFOA. The city’s two other municipal wells showed no detectable PFOA, the press release stated.

PFAS, known as “forever chemicals” because of the amount of time required for the compounds to break down, are linked to a variety of health risks and come from man-made materials.

The city has removed the one affected well from normal operation, meaning the well won’t be used as part of routine water production and will be reserved for emergency use while the city “collects additional information and evaluates its longer-term options.”

The city isn’t issuing a do-not-drink or do-not-use advisory, so customers may continue using city water for drinking, cooking, bathing, and other normal household purposes, the press release stated. 

“The City’s immediate priority is protecting public health and providing clear, accurate information,” City Manager Eric Hanks said in the press release. “We removed the affected well from routine operation after our other two wells returned nondetect results. Water customers will continue to receive normal City water pressure and quantity. 

“We will continue to work with Montana DEQ (Department of Environmental Quality) to evaluate all available information. More information and links to EPA and Montana DEQ resources are available on the City’s website.”

Following a June 2026 sample from the affected well that reported PFOA at 8.1 parts per trillion, confirmation samples were collected in September. Those confirmation samples reported 7.0 parts per trillion in raw water from the well, and 7.2 parts per trillion at the entry point to the distribution system. The EPA’s Maximum Contaminant Level (MCL) for PFOA is 4.0 parts per trillion. 

The initial June sampling wasn’t a result of a suspected contamination in the Columbia Falls water system, but instead was part of the EPA’s Fifth Unregulated Contaminant Monitoring Rule, known as UCMR 5. The monitoring is part of a nationwide effort to collect information about the occurrence of PFAS in drinking water supplies. Public water systems must begin complying with the federal standard in 2029. 

“Although the recent results from the affected well exceed 4.0 parts per trillion, these two samples alone do not constitute a current federal MCL violation,” the city said in the release.

With the city’s wells supplying an integrated distribution system, water from the three wells “may blend throughout the network,” the release stated. The affected well is the city’s oldest municipal well and is located on a former industrial sawmill property south of U.S. Highway 2. 

“The source of the PFOA has not been determined,” the release stated Tuesday. “Because groundwater can travel through the aquifer before reaching a well, the well’s location does not establish the location or source of the contamination. The City is not attributing the detection to any property owner, business, industrial or commercial activity, or other potential source.”

The EPA states that exposure to some PFAS, including PFOA, has been linked to potential effects involving pregnancy and development, immune response, cholesterol, the liver, and an increased risk of some cancers. 

“These associations do not mean that a health effect will occur in an individual because of a particular test result,” the city said. “Anyone with health questions or concerns is encouraged to speak with their medical provider for guidance based on their individual circumstances.

The city is conducting additional, non-regulatory sampling of the affected well and related water system facilities through a separate qualified laboratory. Results from EPA’s UCMR 5 monitoring and Montana DEQ’s regulatory water-testing process will remain the city’s primary basis for regulatory reporting. 

“The City will review all available information with state regulators before making longer-term decisions,” the city said. 

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