A chlorine bleach solution may be used to remove odors from basements that have been flooded, said Mary Yearns, Iowa State University Extension housing specialist.
After checking the structural safety of the basement and removing water and mud, use a coarse brush or long-handled broom to scrub down the floors, walls and ceiling.
“First, spray surfaces with lukewarm water to remove flood residue,” Yearns says. “Start with the floor then move to the bottom of the walls and work your way up. This will lessen the chances of leaving muddy streaks on any basement surfaces.”
Next, use hot water with a heavy-duty cleaner to scrub all surfaces, again, starting at the bottom and working up to the top. Follow up with a rinse using a brush moistened with a solution of two tablespoons chlorine bleach per gallon of water. Repeat the scrubbing and rinsing until the odor is gone.
“You’ll want to dry out the basement, but if the outdoor air is humid, don’t open the windows to do it,” Yearns says. It’s better to run central air conditioning or a dehumidifier. These methods will remove moisture from the basement air. Running a fan also will help dry things out.
Source: Iowa State University Extension Service