An urban rat expert shares tips for D.C.'s rodent issues

• It's a simple rule-of-thumb to follow when you have a rat problem, according to Corrigan, who has a Ph.D. in urban rats studies and advises cities, including the District.

The details: He says residents should spray their garbage cans and trash bags with 10% bleach solution when taking out trash.

• “The rats do not like to chew into bleach tasting anything,” he says. “If the outside of the can smells like bleach to that famous nose of theirs, they're like, 'Well, this ain't food.’”

Keeping garbage cans tightly closed is also imperative and requires cooperation from everyone in a neighborhood.

• “If those rats show up in that alley night after night, and everything's tidy, and everything's been cleaned up, and everything's in tight cans, and so forth — if they don't get food, they don't come to that alley anymore,” he says. “Period.”