The Twin Cities metro's PFAS story is unlike any other in the country because it has a single, identifiable corporate origin.
The Twin Cities metro's PFAS story is unlike any other in the country because it has a single, identifiable corporate origin. Minneapolis draws drinking water from the Mississippi River. St. Paul pulls from a chain of lakes and the Mississippi. Together, the metro serves 3.7 million people across a seven-county area. The water itself would be unremarkable – Upper Midwest surface water, cold and relatively clean – if not for what happened on the eastern edge of the metro.
3M's Cottage Grove and Oakdale facilities manufactured PFAS compounds for decades, and the contamination from those operations has become one of the largest environmental remediation cases in American history.
The eastern Twin Cities suburbs – Woodbury, Cottage Grove, Lake Elmo, Oakdale – sit atop a groundwater plume contaminated by 3M's PFAS manufacturing waste. In 2018, Minnesota reached a \$850 million settlement with 3M to fund drinking water treatment and remediation in the affected area. The Minnesota Pollution Control Agency (MPCA) has mapped the contamination plume extending across miles of suburban communities.
Minnesota set health-based guidance values for several PFAS compounds, including 35 ppt for PFOA and 300 ppt for PFOS (these are advisory, not enforceable MCLs). The Minnesota Department of Health has been conducting granular monitoring of individual wells and water systems in the contamination zone since 2006.
According to MPCA data, PFAS concentrations in some east metro monitoring wells have exceeded 10,000 ppt. Municipal treatment systems installed with settlement funds have brought tap water levels below state guidance values in most affected communities, but the contamination itself persists in the aquifer.
Minneapolis and St. Paul proper, drawing from surface water, face lower PFAS concentrations. But the Mississippi River receives wastewater effluent from upstream communities, and detections have been confirmed in both cities' finished water.
The Twin Cities metro has more PFAS monitoring data per capita than perhaps any metro in the country, thanks to the 3M litigation and state-mandated testing. That transparency is a double-edged sword: residents here know more about what's in their water than residents of metros with less testing, which can make the situation appear worse by comparison even when actual tap water levels are now managed.
Nationally, the 3M settlement and subsequent treatment investments mean that affected east metro communities now have dedicated PFAS treatment that many contaminated communities elsewhere lack. The irony is that the worst contamination origin produced some of the most advanced remediation.
See our Minnesota state page for statewide patterns.
Location within the metro is everything here. West of the metro core, PFAS risk is low. East metro communities in the 3M plume area have treatment systems in place but should still monitor their data closely.
Check your water to see current readings for your provider. If you're in Washington County or east Dakota County, pay particular attention to the specific PFAS compounds listed – some that 3M produced are not covered by federal MCLs. Our water filter guide covers activated carbon and ion exchange systems appropriate for Minnesota's contamination profile. For historical data showing how levels have changed since treatment began, pull a detailed report.