When anything remains wet for more than two days, mold begins to form, according to the EPA. There also may be germs and bugs in your home after a flood.
So, you need to begin cleanup efforts as soon as possible. The EPA recommends that you protect yourself as you clean, wearing an N-95 respirator (available at hardware stores), goggles, gloves, long pants, long-sleeve shirt, and boots or work shoes.
The Federal Emergency Management Agency and the American Red Cross offer a booklet, Repairing Your Flooded Home, that contains standard advice, as well as lessons learned from the worst-case scenario created in New Orleans by Hurricane Katrina seven years ago.
Don't rush to move back in. After a house has been flooded, it must be thoroughly cleaned and dried to be habitable again.
It's understandable that people want to return to their homes after a flood, but they often don't realize what they may be facing. Just opening doors may be difficult because the water has made the wood swell. Plaster ceilings and walls may be water-logged and heavy. Floorboards may have come loose, joists may be weakened, and there could be holes and exposed nails.
Before you go back inside, have a professional shut off your electricity and gas. Water damage to lines and pipes can bring with it danger of electrocution or explosion, and you need to be absolutely certain the service has not been compromised.
If it has, and you acquire a gasoline-powered generator to operate lights and fans to aid in the cleanup, do not run it indoors or in closed-in areas. The same goes for gas grills and power-washers.
Post-disaster carbon monoxide poisoning is a growing problem, one cited in a 2001 article in the Journal of Emergency Medicine. Health authorities found that all the incidents of carbon monoxide poisoning in the aftermath of the 1997 flooding in Grand Forks, N.D., involved the use of gasoline power washers in basements.
Government experts recommend not pumping out a flooded basement until most of the water is gone. To do otherwise could result in the walls collapsing.
Once the water levels have dropped, test the plumbing and basement drains by pouring in a bucket of water. If the water does not run out, remove the clean-out plug from the trap and rake out the mud with a wire.
Dry out, smell sweeter. Open doors and windows to ventilate and dry the interior of a flooded house. But once the electricity is back on and in working order, you should use fans and air conditioning rather than letting in damp and humid air, which will prolong the process.
Wait until floors, ceilings, walls, and furnishings are dry and free of mold and mildew before trying to repair or salvage any of them. Once fully dry, buckled floors can be drawn back into place with nails; humps may be removed by planing and sanding.
The odor associated with flooding can be overwhelming, though it is likely to pose a risk only to some people with respiratory issues. That said, you want to try to get rid of odors as soon as you can.
Remove water and mud with a broom or wet-dry vacuum, then spray surfaces with lukewarm water, starting with the floor, moving to the walls and working up. Use a coarse brush or long-handled broom to scrub the surfaces.
Using hot water and a heavy-duty cleaner, scrub all surfaces again, from the bottom to the top. Follow with a rinse using a brush moistened with a solution of two tablespoons of chlorine bleach per gallon of water.
Repeat scrubbing and rinsing until the odor is gone.
To disinfect after sewage has flooded a space, use a solution of one part chlorine bleach to nine parts clean water. You can use rock salt on hard surfaces such as plaster and painted drywall, but not on concrete floors, which salt will damage. Use one cup of rock salt per gallon of water.
Never mix bleach and ammonia. The combination produces hazardous fumes.
Dos and don'ts:
Get rid of soaked carpeting. If the damage is slight, drape the carpet over a sawhorse or chairs to drain, but don't dry it this way or it can stretch out of shape. Have the carpet cleaned professionally, or rent a steam cleaner. If the carpet must stay in place, use a wet-dry vacuum to clean up mud and water.
If walls in a flooded space are insulated, you may need to remove the baseboards to ventilate wall cavities. The insulation might have to be removed and replaced.
Plaster walls and washable vinyl wallpaper can be cleaned. Allow the plaster to dry thoroughly before washing it. Use a mild soap and water to clean painted walls. If you have to repaint, wait a couple of months for the walls to dry completely, or the new paint will blister.
Contact Alan J. Heavens at 215-854-2472, firstname.lastname@example.org or @alheavens at Twitter.