A recent report by the University of Montana Flathead Lake Biological Station found pollutants in a number of shallow wells in the Evergreen area, though health officials say the study raises concerns only for drinking water from private wells and not heavily regulated public water supplies.
The 17 wells analyzed in the report are shallow private wells no deeper than 31 feet. Public water supplies, whether municipal or as part of a subdivision, often reach down hundreds of feet into confined aquifers that yield clean water, Flathead City-County Health Department Officer Joe Russell said.
The state Department of Environmental Quality does not approve new wells shallower than 25 deep for public use or for use in new subdivisions.
“The majority of public water supply wells generally take water from deep aquifers that are not subject to the same problems,” Shelley Nolan of the DEQ’s public water supply program said.
Russell and Nolan said public water supplies are closely monitored and routinely tested for contaminants. Nolan added that some of the contaminants listed in the report aren’t regulated under the Clean Water Act and more research is required before drawing any conclusions.
“At this point it’s hard to say at those levels whether or not they would be significant to public health concerns,” Nolan said.
The wells in the study are located in a “shallow, unconfined alluvial aquifer” spanning the area between the Flathead and Whitefish rivers roughly from Evergreen up to Montana Highway 40, Russell said. This aquifer represents a “distinct geological area” and is not used in municipal water supplies, he said.
“In the middle of the north Flathead Valley surrounding Kalispell we have a wonderful confined aquifer and it yields wonderful unpolluted water,” Russell said, adding that public water supplies in nearby towns and unincorporated areas such as Evergreen and Bigfork also have clean drinking water.
“We don’t recommend the use of shallow wells for drinking water,” he added.
According to the DEQ, the samples were taken from “a small group of shallow wells in an area of the valley known to be vulnerable to seepage from surface and ground sources, septic tank leakage and other pollution sources.”
Russell said the report “found a whole sweep of different types of pollutants,” though “none of them are in overly high concentrations.” Among the contaminants are microbiological pollutants, volatile organic chemicals and pharmaceutical and personal care products.
“The study has validity to show that these shallow unconfined aquifers are very sensitive to pollution and finding different types of pollutants reinforces that,” Russell said.
Russell and DEQ officials recommend that landowners with private wells test for contaminants. Labs such as the Montana Environmental Lab in Kalispell offer testing kits and information. If contaminants are found, Russell said there are “treatment modalities that be used that are very similar to what you would use to treat lake water before you drink it.”
“If people are using shallow wells, they should test their waters to see if they’re safe,” Russell said.