When Keith Rapp gets a drink from his kitchen, it’s quite a process.

The water comes in through a filter on the back of his refrigerator, then through another filter inside the fridge. From there, Rapp fills a Brita pitcher, then a water bottle with its own carbon filter in the cap.

“This will be the fourth filtration of this water,” he said, taking a sip from the bottle. “That’s how we do water here.”

Rapp lives in the east Twin Cities metro where the groundwater was contaminated by chemicals produced for decades by 3M.

Officially, the city water here is safe to drink. But Rapp, a hydrogeologist who deals with groundwater contamination for a living, said he’s worried about the possible effects of perfluorochemicals since he first learned of their presence more than a decade ago. “I knew what the potential risks were,” he said.

Rapp and many others across Minnesota and the U.S. will be watching closely this week as the state’s $5 billion lawsuit against 3M for polluting natural resources finally goes to trial after years of delays.

Jury selection is expected to start Tuesday in Hennepin County District Court in Minneapolis. The trial is expected to last four to six weeks.

The state alleges that 3M knew decades ago about risks linked to its chemicals that wound up in the groundwater in the east metro. Whether those chemicals have actually caused health problems for Minnesotans is expected to be a key question in the trial.

The trial could set a precedent as 3M faces at least two dozen lawsuits related to PFCs around the country.

“These cases and the ultimate potential liability for these companies I think is extremely important, and does force them to essentially consider more of the impacts these chemicals can have over a lifetime,” said David Andrews, a senior scientist with the Environmental Working Group, a national environmental advocacy organization.