Practical Guide: What to Do When Your Basement Floods

What to do when your basement floods starts with staying out of the water until the power is off and you know what is in it. Stop the source if you can, photograph everything, call your insurer, then remove the water gradually and start drying within 24 to 48 hours to prevent mold.

What to do when your basement floods: safety first

• Electricity. If water reaches outlets, appliances or the breaker panel, do not enter. Switch off power at the main breaker only if the panel is dry and you are not standing in water. Otherwise call your electric utility or an electrician.
• Gas. If you smell gas, leave the house and call your gas utility from outside.
• Contamination. Floodwater and sewage carry bacteria. Wear rubber boots, waterproof gloves, eye protection and an N95 mask, and keep children and pets out.
• Structure. Do not go in if you see cracks, bowing walls or a sagging ceiling.

Find and stop the source

Source	What to do
Burst pipe or failed hose	Shut off the main water valve; see what to do when a pipe bursts
Water heater or washing machine leak	Turn off its supply and power
Sump pump failure or power cut	Move to a backup pump if you have one; do not wade in to restart it while wet
Sewer backup	Stop using water and call a plumber; treat everything as contaminated
Heavy rain, groundwater, window wells	Wait for outside levels to fall before pumping

Document before you move anything

Take photos and video of the water level, the damage and the contents. List the items affected. Keep every receipt. Do not throw out damaged belongings until your insurer says you can.

Call your insurer early

Water damage claims depend on the cause: a burst pipe, a sewer or sump backup, and rising floodwater are treated very differently, and a standard homeowners policy often excludes the last one. Our guide on whether homeowners insurance covers basement flooding explains the difference.

Remove the water safely

For a small amount, use a wet and dry vacuum and mops. If the flooding came from rising groundwater or storm runoff, FEMA guidance is to pump the water out gradually, roughly a third each day, rather than all at once, because emptying the basement while the soil outside is still saturated can stress or crack the walls. Wait until floodwater outside has receded before you start pumping.

Dry it out within 24 to 48 hours

Mold can begin growing within 24 to 48 hours. Run fans and a dehumidifier, open windows when the air outside is drier than inside, and move wet items out to dry. Remove soaked carpet padding, insulation and wet drywall. If the water came from a sewer backup or flood, discard porous items that were soaked, such as carpet, mattresses and cardboard.

What to throw away and what to save

Throw away anything porous that stayed wet beyond a day or two, or that touched sewage or floodwater: carpet and padding, insulation, wet drywall, particleboard furniture, mattresses, cardboard boxes, stuffed toys and food. Solid wood furniture, and hard items made of metal, glass or plastic, can usually be dried, cleaned and disinfected. Do not switch on wet electronics or appliances; have them checked first. Wet photographs and papers can be rinsed gently and dried flat or frozen until you have time to deal with them.

Clean and disinfect hard surfaces

Scrub hard surfaces with detergent and water first, then disinfect following the product label. Never mix bleach with ammonia or other cleaners. Let everything dry fully before rebuilding.

When to call a professional

• Sewage or other contaminated water is involved.
• A large area is wet, or the water has reached walls above the baseboard.
• You see structural cracks or movement.
• Mold covers more than about 10 square feet, which is the EPA's rule of thumb for bringing in a professional.
• A furnace, water heater or electrical panel was submerged; have it inspected before using it.
• You cannot get the space dry within two days.

Prevent the next one

A sump pump with a battery backup, downspouts that discharge well away from the foundation, grading that slopes away from the house, window well covers and a backwater valve on the sewer line are the most effective measures. Our water damage guides can help you find help in your city.