PFAS — odorless and colorless — are an invisible threat in our drinking water supply.

“It’s a forever chemical, this isn’t going away,” declares Dave Schulenberg, executive director of the Minnesota Water Well Association. “We’re going to have to understand it, live with it, treat it, remediate it.”   

The Minnesota Pollution Control Agency says those chemicals are now in 22 water systems in 17 cities.

RELATED: PFAS in drinking water: MPCA says forever chemicals are in 22 water systems, in 17 cities

The agency is now sharing a map showing where a PFAS plume is heading in the east metro in coming decades — from the St. Croix River to the west, drifting toward Woodbury and Afton to the south, Lake Elmo to the north, and Maplewood to the west.

“It’s not biodegradable,” Schulenberg says. “You can’t throw it out into the sun and have it become nothing like you can with other contaminants.”

Woodbury is one of the seventeen cities where PFAS levels are above the EPA’s new safety standard of four parts per trillion.

Public Works Director Mary Van Milligen says her city is prepared to handle the forever chemicals, spending millions to filter out PFAS from city wells.

But she warns untreated water may have to be used during high-use summer months.

“We will have to operationally bring in wells with PFAS on occasion to meet the water demand when use is really high,” she says.  

So, we wondered — how to filter out PFAS from the water coming into your home?

The Minnesota Department of Health has several suggestions, including a method called reverse osmosis.

MDH’s website says the devices use ‘energy to push water through a membrane with tiny pores,’ stopping many contaminants while allowing water to pass through.

Health officials say reverse osmosis should be used as a point-of-use treatment option, under a kitchen sink, for example.

“The reverse osmosis treatment system is exactly that — it’s a filter,” explains Paul Wotzka, president of the Minnesota Well Owners Organization. “It’s pushing water through a semi-permeable membrane. On one side of that membrane is all the dissolved particulates in water and on the other side of that membrane is almost pure water.”

MDH says Ion Exchange Resins are also an option, where contaminants are attracted to tiny beads of resin, which keep the materials from passing through a water system.

The website says the systems may remove PFAS, but that users should check to make sure a system they’re considering meets National Science Foundation or American National Standards Institute guidelines.  

Experts say the best filter is granulated active carbon or GAC.

The devices using GAC can also be installed at a point-of-use location, like a kitchen sink.  

“It’s charcoal that has been made to absorb any organic molecule that passes by it, mainly PFAS, and in a lot of well water, pesticides,” Wotzka notes.

GAC is also used in point-of-entry systems about the size of a water softener.

The chief advantage, experts say, is that your whole house is safeguarded against PFAS.

“So, this would go on your water system before it goes to any of your faucets, sinks, showers or anything like that,” Schulenberg says. “So, it’s treated as it comes into the house, not as it’s being used. That way, you’re not worrying about while you’re in the shower. You can cook with water and things like that.”

Retailers say they’re beginning to see an uptick in sales of these devices.

Prices can range anywhere from several hundred dollars to thousands of dollars.  

Schulenberg says homeowners might consider having a full water test done for PFAS before deciding what to do.

He adds there are some state, county, or city programs where people can apply for financial assistance.

“Is this the new normal?” Schulenberg asks. “Yes. The more we look for it, the more we’re going to find it, and the more we’re going to have to deal with it.”

You can find more guidance about PFAS filtration from the Minnesota Department of Health here.