We are paid when readers call a provider through this site. That never changes our advice. How we make money

Quick answer

Stay out of the water until the power to the basement is off, and leave the house if you smell gas. Then stop the source if you can, photograph everything, call your insurer, and remove the water. If the ground outside is soaked after a flood, pump the basement down slowly, about a third of the water per day, so the walls do not crack. Dry everything within 24 to 48 hours and throw out soaked porous items like carpet, padding and drywall.

Do this first: make the basement safe

If you have standing water, turn off the main power only if you can reach the panel from a dry spot. Otherwise call an electrician or your utility to shut it off. Never switch power on or off, or use an electric tool, while standing in water. [1]

Stop and leave if you smell gas

Do not turn on lights or do anything that could make a spark. Leave the house and call the gas company, police or fire department from outside. Do not go back in until you are told it is safe. [1]

  1. Keep children and pets away from the basement until cleanup is done. [2]
  2. Turn off power to the basement at the panel, only from a dry spot. Have an electrician check the system before it goes back on. [1]
  3. Stop the water if you can: close the main water valve for a burst pipe, or the supply valve for a water heater or washer.
  4. Stop using sinks, toilets and the washer if water is coming up through a floor drain. That water may be sewage.
  5. Take photos and video of the water and damage before you move anything. [3]
  6. Call your insurance company as soon as you can to open a claim. [4]
  7. Move dry belongings upstairs and lift what you can off the wet floor.

Treat sewage and floodwater as Category 3, grossly unsanitary water that can carry germs. [5] Wear rubber boots, rubber gloves and goggles, and cover any cuts with a waterproof bandage. [6]

Stay out from under any ceiling that sags or bulges. Leave if you hear shifting or strange noises, which can mean part of the building is about to fall. [2]

Never run a gas pump or generator in the basement

CDC says never run a gasoline pump, generator or pressure washer inside a home, basement or garage, or less than 20 feet from any door, window or vent. [1]

Where is the water coming from?

The source decides how dirty the water is and which insurance may apply. Restoration work uses three categories: Category 1 is clean water, Category 2 is gray water with significant contamination, and Category 3 is sewage or other contaminated water. [5]

Common basement water sources, their usual category, and the first thing to do
SourceUsual categoryFirst action
Burst or broken supply pipeCategory 1 (clean)Close the main water shutoff valve.
Leaking water heaterCategory 1 (clean)Close the cold water valve on the heater. Turn off its power or gas only if you can reach it from a dry spot.
Washing machine overflow or drain waterCategory 2 (gray)Close the supply valves behind the washer and stop running it.
Sump pump failureCategory 2 (gray)Check whether the pump lost power or the float is stuck. Do not reach into water near a plugged-in pump.
Groundwater seeping through walls or floorCategory 2 (gray)Wait for the rain to stop and the ground outside to drain before pumping.
Surface flooding from heavy rain or a rising river or streamCategory 3 (black)Wait until floodwater no longer covers the ground outside, then pump slowly.
Sewer backup through a floor drain or toiletCategory 3 (black)Stop using all water in the house. Call a plumber or your sewer utility.

These examples follow the IICRC standard as summarized by UC Riverside and by Massachusetts public health guidance. [5] [7] Gray water in a flooded building that is left untreated for longer than 48 hours may change to Category 3. [5]

With a sewer backup, ask your sewer utility whether the clog is in the public main or your own service line. Some districts, such as Colorado's Bowmar Water and Sanitation District, say they will help make that call. [8]

How to get the water out without cracking the walls

For a shallow leak, a wet/dry shop vacuum works. For more water, CDC lists an electric transfer pump or sump pump, used only after an electrician says the power is safe. [1]

Deep water after a flood needs patience. The American Red Cross says to pump a flooded basement out gradually, about one third of the water per day, because pressure from water-soaked soil outside can collapse the walls if you pump too fast. [9] FEMA gives this routine: [10]

  1. Start pumping only when floodwater no longer covers the ground outside.
  2. Pump out 1 foot of water. Mark the water level and wait overnight.
  3. Check the level the next day. If the water rose back over your mark, it is still too early. Wait 24 hours and pump 1 foot again.
  4. When the water stops coming back to your mark, pump out 2 to 3 feet and wait overnight.
  5. Repeat each day until the basement is empty.

FEMA notes that rebuilding collapsed walls could cost more than the flood cleanup. [10] The risk comes from saturated soil, so a burst pipe on a dry day does not create it.

Safe to do yourself

A small amount of clean water from a pipe, water heater or washer supply line, with the power safely off. A wet/dry vacuum, fans and a dehumidifier can handle it if you start right away.

Dry it out within 24 to 48 hours, and decide what to keep

EPA says to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth in most cases, and to keep indoor humidity below 60 percent. [11]

  1. Open windows and doors if the weather allows.
  2. Run fans and dehumidifiers. Point fans out a window or door. [1]
  3. Do not run a furnace or air system that sat in floodwater until a professional checks and cleans it. [1]
  4. Pull up vinyl flooring and tile if needed so the subfloor can dry. [9]
  5. Have any flooded appliance checked by a professional before use. [9]

CDC says to throw away anything you cannot clean or dry quickly. [2]

  • Usually throw out: carpet and carpet padding, rugs, mattresses, upholstered furniture, pillows, foam rubber, stuffed animals, baby toys, books, paper products, wall coverings and cosmetics. [2]
  • Cut out: drywall and insulation touched by sewage or floodwater. [2] With clean water, cut out wallboard that has not dried within 48 hours. [7]
  • Usually keep and clean: concrete, molding, wood and metal furniture, countertops, appliances and plumbing fixtures, washed with hot water and detergent. [2]
  • Food: throw away food that touched floodwater. When in doubt, throw it out. [1]

The Red Cross says structural parts of a home can take weeks or months to dry fully. Replace drywall, carpet and flooring only after that. [9]

Document it for insurance, then learn what each policy covers

  1. Take photos and video of the damage. Photograph the make, model and serial number of appliances and electronics. [3]
  2. Make a detailed list of damaged or lost property. [4]
  3. Keep samples of carpet, flooring and curtains. [3]
  4. Ask your adjuster before throwing out damaged property. If you must discard items for safety, photograph them first. [4]
  5. Hold off on permanent repairs until your insurer approves them. [4]
  6. Keep receipts for pumps, fans and cleaning supplies.

The Wisconsin insurance regulator puts it simply: water from the top down is generally covered by a standard homeowners policy, and water from the bottom up is not. [4]

How basement water is usually covered (check your own policy)
PolicyUsually coversUsually does not cover
Standard homeownersSudden and accidental leaks, such as a burst pipeFlood, seepage through the foundation, gradual leaks, and in most policies mold
Flood insurance (NFIP)Water entering from the ground up, such as heavy rainfall or an overflowing body of water. In basements, only listed items: installed furnaces, central air units, sump pumps, outlets and switches, plus washers and dryers with contents coverageMost belongings stored in a basement, finished basement walls and floors, and mold
Sewer backup or sump pump overflow endorsementWater that backs up through drains or overflows a sumpFlood, which needs a separate flood policy

Behind the table: sudden leaks are usually covered while gradual leaks, a leaking foundation and most mold are not. [12] [4] Most homeowners policies exclude flood. [13] NFIP covers ground-up water and only installed, powered items in a basement. [3] Basement belongings and finished walls and floors are excluded. [14]

Sewer backup is the gap people miss. The Wisconsin regulator says neither homeowners nor flood insurance covers sewer backup or sump pump overflow without a special endorsement. [4] FloodSmart notes one exception: a flood policy would cover a sewer that backs up during a heavy rainstorm, but not one caused by clogged pipes. [13] Under the NFIP, a flood means water covering 2 or more acres of normally dry land or 2 or more properties, one of them yours. [15]

NFIP claims can take 4 to 8 weeks to be paid. FloodSmart advises talking to your agent or adjuster before you sign a contract with a cleanup contractor. [3]

What does flooded basement cleanup cost?

HomeAdvisor's flooded basement cost guide, updated June 19, 2026, puts most cleanup jobs at $2,000 to $7,000, with an average of $4,000. Its low end is $1,500 and its high end is $15,000. By size, it estimates $3 to $7 per square foot, or $3,000 to $7,000 for a 1,000 square foot basement. [16]

Dirty water costs more. HomeAdvisor's June 2026 figures for cleaning only are $1,500 to $3,500 for Category 1, $3,000 to $7,000 for Category 2, and $7,000 to $15,000 for Category 3. Repairs after drying are extra. [16]

How to keep it from happening again

  • Sump pump with battery backup. FEMA recommends a backup that runs during a power failure. [17]
  • Backflow (backwater) valve. Have a plumber install one so water and sewage cannot back up into the house. [17]
  • Grading. The ground around the house should slope away so water drains off, not toward the basement. [1]
  • Gutters and downspouts. Keep them clear so roof water drains away from the house. [17] [1]
  • Seal foundation cracks. FEMA suggests mortar and masonry caulk for cracks and for openings where pipes and wires enter. [17]
  • Raise utilities. FEMA suggests moving heating, electrical and plumbing equipment to the flood protection level your local code requires. [17]
  • Check your coverage now. NFIP flood policies typically have a 30-day waiting period before they take effect. [13]

When to call a water damage restoration company

Small, clean leaks can often be handled at home. HomeAdvisor's June 2026 guide notes that if your whole basement is under more than an inch of water, you will likely want professional help to pump it out. [16] Call one when:

  • Sewage or outside floodwater is in the basement.
  • Water is near outlets, cords or the electrical panel.
  • Standing water covers the whole floor.
  • Drywall, carpet or insulation is still wet after 24 to 48 hours.
  • You cannot find the source, or it seems to be inside a wall.
  • Mold covers more than about 10 square feet. [11]

Common questions

Who do I call when my basement floods?

If you smell gas, leave and call the gas company or fire department from outside. If water is near the electrical panel and you cannot reach it from a dry spot, call your utility or an electrician. Then call your insurance company to start a claim. For a burst pipe or sewer backup, call a plumber, and for standing water, sewage or large drying jobs, call a water damage restoration company that serves your area.

Is it safe to live in a house with a flooded basement?

It depends on the hazards. Do not stay if you smell gas, hear shifting or strange noises, or have water near live electrical parts. CDC also says to keep children and pets away from the affected area until cleanup is done. If you have health concerns about mold or sewage exposure, ask your doctor.

What to do if your basement floods with sewage?

Treat it as Category 3 water. Stop using all sinks, toilets and appliances that drain, keep children and pets away, and wear rubber boots, rubber gloves and goggles if you must go in. Throw out porous items and drywall or insulation that sewage touched. Sewage cleanup is a job where a restoration company is often the safer choice.

How much does it cost to unflood a basement?

HomeAdvisor's June 19, 2026 guide puts most flooded basement cleanups at $2,000 to $7,000, with an average of $4,000 and a range of $1,500 to $15,000. Clean water costs the least, and sewage cleanup runs $7,000 to $15,000 for cleaning alone. Repairs after drying are extra.

How fast should I pump water out of a flooded basement?

If the ground outside is still soaked after a flood, go slowly. The Red Cross advises about one third of the water per day, and FEMA suggests pumping 1 foot, then checking overnight whether the water comes back. Pumping too fast can crack or collapse basement walls.

Does homeowners insurance cover a flooded basement?

Usually only when the water came from a sudden, accidental source inside the house, like a burst pipe. Flooding from outside needs flood insurance, and sewer backup or sump pump overflow usually needs a separate endorsement. Read your own policy or ask your agent.

Sources

  1. Safety Guidelines: Reentering Your Flooded Home Centers for Disease Control and Prevention, accessed October 12, 2026
  2. Guidelines for Cleaning Safely After a Disaster Centers for Disease Control and Prevention, accessed October 12, 2026
  3. How to start a flood insurance claim FloodSmart (National Flood Insurance Program), accessed October 12, 2026
  4. Frequently Asked Questions: Flood Damage (PI-240, rev. 10/2024) Wisconsin Office of the Commissioner of Insurance, accessed October 12, 2026
  5. Water damage guidelines (follows IICRC S500) University of California, Riverside, Environmental Health & Safety, accessed October 12, 2026
  6. Clean Up Safely After a Natural Disaster Centers for Disease Control and Prevention, accessed October 12, 2026
  7. Quick reference: water damage response in buildings Commonwealth of Massachusetts, accessed October 12, 2026
  8. Sewer Line Responsibility and Insurance Coverage (February 21, 2024) Bowmar Water and Sanitation District (Colorado), accessed October 12, 2026
  9. Disaster Cleanup and Repair For Your Home American Red Cross, accessed October 12, 2026
  10. Don't Pump Out Basements Too Early or Too Fast (release FS-19, August 22, 2019, archived) FEMA, accessed October 12, 2026
  11. A Brief Guide to Mold, Moisture and Your Home U.S. Environmental Protection Agency, accessed October 12, 2026
  12. Leaks, water damage and mold Washington State Office of the Insurance Commissioner, accessed October 12, 2026
  13. What's covered FloodSmart (National Flood Insurance Program), accessed October 12, 2026
  14. What Does Flood Insurance Cover in a Basement? (fact sheet) FEMA / National Flood Insurance Program, accessed October 12, 2026
  15. Glossary: Flood FEMA, accessed October 12, 2026
  16. How Much Does a Flooded Basement Cleanup Cost in 2026? (updated June 19, 2026) HomeAdvisor, accessed October 12, 2026
  17. Be Flood Smart. Protect Your Property (July 16, 2024) FEMA, accessed October 12, 2026