Buy out the residents, help them relocate, demo the properties and prevent them from ever being purchased again. FEMA has a similar initiative and funding for properties that continually flood after natural disasters [1].

Due to Illinois finances, federal funding is likely required to accomplish this. Success is more likely than what would be necessary to keep these residents in place and fix the systemic issues that caused this to occur.

If you’re in Illinois, consider forwarding this to your senators, and the House reps for these people. They’ll need funding for the Illinois EPA to administer the buyouts.

[1] https://www.fema.gov/news-release/2014/05/28/communities-pla...