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How To Clean, Dry, and Repair a Flooded Basement

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Vacuuming up water from a leaking residential domestic water heater

Default Author Icon Written by Angela Bunt Updated 04/22/2024

A flooded basement can be a source of dread for homeowners, whether due to heavy rain, melting snow, or a burst pipe. You must contend with the immediate water damage, decide what to do with the damaged items, and determine whether your insurance company will cover expenses. Plus, you’ll need a plan to stop basement flooding in the future. 

We’ll take you through the complete basement flooding repair process so you know what to do.

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Step 1: Immediate Response

Once you realize your basement has flooded, take the following steps immediately. If a severe storm caused the flood, wait until it’s over before heading downstairs.

Here’s a step-by-step guide to follow:
Shut off the power: To avoid the risk of electric shock, find your main electrical panel and shut off the breakers controlling power to the basement. If you have any uncertainty about which breakers are correct, or if the panel is wet, call a qualified electrician.
Check for a gas leak: Be aware of other potential hazards before entering your flooded basement. If you smell gas, evacuate the house immediately and then call your gas company and the fire department from a safe location.
Assess for structure damage: If you see cracks in the foundation, sagging ceilings, or other signs of instability, the basement might be unsafe to enter. Call a structural engineer for assessment before proceeding.
Wear proper gear: Wear rubber boots and gloves to keep your skin dry and minimize the possibility of electric shock. Wear a face mask (preferably an N95 respirator) to protect your lungs from mold or contaminants.
Look for the water source: Identify the cause of the flood. If it’s a plumbing issue, shut off the main water supply to the house. This valve is typically located near your water meter or hot water heater. It could be in the basement, crawl space, or utility room—or in a panel buried in your yard, near the curb.
Unclog the floor drainage system: If your basement has floor drains, make sure they aren’t blocked or clogged. You want the water to drain as quickly as possible.
Open doors and windows: Improved ventilation will help prevent the growth of mold and mildew. If it’s safe to do so, open basement windows and doors to increase airflow.
Call your insurance company: Depending on the flooding’s cause, your homeowners insurance or flood insurance policy may cover the damage. Call your insurer to find out. You may qualify for professional cleaning services right away.

Step 2: Assessment and Inspection

Inspect the entire basement to measure the extent of damage and identify any hazards. This information is crucial for your insurance claim and to plan safe repairs. Here’s what to look for:

  • Structural concerns: Carefully examine walls, floors, and ceilings. Look for cracks, shifting, bulging, or any changes not present before the flood. If you notice significant structural concerns, immediately call a structural engineer or qualified contractor for a safety assessment.
  • Hidden water: Investigate any signs of hidden water damage, such as water stains, warped surfaces, or dripping sounds. Damage may be lurking behind walls or under flooring.
  • Appliances and utilities: Have a qualified electrician or technician inspect any appliances or utility systems that were exposed to floodwater, such as your laundry machines or water heater.
  • Mold and mildew: Look for signs of mold growth and be aware of musty odors. Mold can develop quickly, so stay vigilant even if it’s not initially visible.

Take detailed photos and videos of the overall basement and specific damaged areas as you go. Create a written list of all damaged belongings, including descriptions, brands, model numbers, approximate age, and estimated replacement costs. You will need this evidence to support your insurance claim if the water damage was caused by a covered event.

Step 3: Water Removal

The scope of the water removal process depends on the amount of water in the basement. Choose the water removal method that best suits the severity of the flooding and your comfort level.  Always prioritize safety, especially if water is near electrical sources.

  • Minor flooding: Use a wet/dry vacuum or buckets to remove smaller amounts of water.
  • Moderate flooding: Rent or install a sump pump to remove the water slowly. Just don’t use a plug-in model if the water reaches any electrical outlets. The Federal Emergency Management Agency (FEMA) recommends pumping out only 1 foot of water every 24 hours to prevent walls from collapsing.
  • Major flooding: Hire a professional water removal company. They have heavy-duty water extractors that get the job done quickly. Your homeowners insurance policy may cover water removal if the flooding was caused by a covered event.

Some basements are already equipped with sump pumps, but you can also buy or rent one at a home improvement store. The best sump pumps cost anywhere from $58 to $520 and can pump up to 5,400 gallons of water per hour, depending on the model. Homeowners have several types to choose from, including battery-powered backups to use during a power outage.

Step 4: Drying and Dehumidifying

Once standing water is removed from the basement, you need to dry and dehumidify. If you hire a professional service, they’ll bring in commercial-grade air movers and dehumidifiers. They use moisture meters to determine how long to keep the equipment running. Some professionals may also bring in air scrubbers to remove harmful particles from the air.

The drying process can also be a do-it-yourself (DIY) project. Here’s how:

  • Ventilation: Open all windows and doors to maximize cross-ventilation, weather permitting.
  • Fans: Set up fans throughout the space, directing airflow towards damp areas, walls, and corners. You can use standard box fans, but renting or purchasing high-powered commercial fans will significantly speed up the process.
  • Dehumidifiers: Buy or rent a dehumidifier with appropriate capacity for your basement’s size and aim to keep relative humidity below 60%. Empty the dehumidifier’s reservoir frequently or set it up to drain continuously.
  • Air conditioning: If you have central air conditioning, running it can help the basement dry out.
  • Removal: Move soaked furniture, rugs, boxes, and other items out of the basement to allow better airflow and prevent further moisture build-up. If possible, take items outdoors to dry in the sun.

The chance of mildew and mold growth increases after 48 hours, so take these steps immediately. Pay special attention to corners, behind appliances, and other areas that are visually obstructed.

Step 5: Cleaning and Disinfecting

Clean and disinfect the basement and everything in it to prevent mold growth and other potential health hazards. Before you start, understand the type of water involved:

  • Clean water: Flooding from a burst pipe or appliance leak usually falls into this category. The exception would be a dishwasher leak, due to the food particles in the water.
  • Gray water: Water from washing machines, dishwashers, showers, tubs, or sinks is considered gray water. It may contain some contaminants.
  • Black water: Flooding from contaminated water sources, such as sewage leaks or floodwater runoff.

If porous materials were contaminated with sewage water or floodwater (which has bacteria), you will likely need to throw them away. This includes carpets, upholstered furniture, and drywall. For clean or gray water, consider taking soft items to a professional cleaner.

Once the basement is clear and dried out, clean hard surfaces thoroughly. Mop concrete floors and walls with a bleach solution of 3/4 cup of bleach per gallon of water. Be sure to open windows and run fans while disinfecting with bleach, wear gloves and a mask, and rinse surfaces afterward.

Always seek professional help for black water contamination. We also recommend hiring a professional for extensive gray water damage or significant mud deposits.

Step 6: Damage Repair

After the water removal phase, you will need to address any other flood damage. For instance, water-damaged outlets, wiring, switches, or any electrical components within the flooded area must be inspected and likely replaced by a qualified electrician. The same may be true of appliances and HVAC components.

Here are a few projects you may be able to handle yourself:

Properly treating mold ensures the air you and your family breathe stays healthy. According to the EPA, it’s safe to tackle mold remediation as a DIY project if the affected area is 10 square feet or smaller. Otherwise, you should hire a professional. People with asthma, allergies, or other health sensitivities might need professional help regardless of the mold patch size. Visible mold is often only a small part of the problem. A musty smell in your basement warrants a thorough inspection and remediation, even if you don’t immediately see mold.
Cement basement floors are usually the easiest to clean, disinfect, and dry after a flood. Consider sealing them afterward to prevent future moisture issues. Carpeting will likely need to be replaced, as will any other floor material that warps or retains moisture. These materials are difficult to properly clean and pose a mold risk. This could be an easy project for many homeowners with basic DIY skills. However, some situations might also involve subfloor repair, which can be more complex.
Basement drywall that remains soft, warped, or discolored after completely drying must be replaced due to structural weakness and mold risk. You may be able to salvage the wall’s upper portion if it stayed completely dry and the exposed framing shows no mold. Replacing drywall can be a DIY project if you’re comfortable demoing the impacted walls and installing replacement pieces. However, it can be challenging to match the wall texture and work around electrical or plumbing elements
Water-damaged ceiling drywall must always be fully replaced, even if it has dried. It loses strength and is a mold risk. If the leak caused only minor staining without affecting the drywall itself, cleaning and repainting might be enough. You can spot-treat affected areas and gauge whether to hire a pro based on your drywalling skills. However, ceiling repairs can be more complex than wall repairs, and you should call a professional if you notice any signs of damage to the joists or subfloor.

Step 7: Future Flooding Prevention

Once the water damage restoration process is complete, take steps to prevent basement water issues—especially if the area is at high risk of flooding again. Here are a few ideas:

  • Waterproof paint: You can apply a waterproof coating to concrete or cement surfaces in your basement or crawl space to minimize future structural damage.
  • Drainage improvements: Prevent water damage from the home’s exterior by installing gutters and downspouts and landscaping that grades away from the house.
  • Sump pumps: Install an electric sump pump to remove water as it comes in. Add a battery-powered or water-powered backup in case power goes out during a storm.
  • Leak detection system: Place water detection devices near any appliances that use water (such as a water heater or washing machine). The device will sound an alarm to notify you to shut off the water when there’s a leak.

Check out the video below to learn more about sump pumps and leak detection devices:

When To Hire a Professional

While some water damage scenarios might be suitable for DIY, calling a professional is often the safest and most efficient route. They have the proper equipment for removing water, sanitizing the area, and removing mold or mildew. Hiring a professional is especially important if any of the following are present:

  • Extensive flooding: Significant amounts of water or flooding from multiple sources can overwhelm DIY capabilities and increase the risk of improper drying.
  • Sewage contamination: Black water poses serious health risks and always necessitates professional remediation specialists with specialized training and equipment.
  • Structural damage: Signs like major foundation cracks, sagging walls, or warped framing warrant a structural assessment that only a qualified professional can provide.
  • You feel overwhelmed or uncertain: If the scope of the damage feels daunting, or you have any doubts about your ability to thoroughly dry, sanitize, and repair the area, calling in help is the wisest choice.

Check with your home insurance company to ask if they work with local vendors. This can expedite the repair or claims process. The insurance company may also pay recommended vendors directly. Read online reviews to choose a reputable restoration company for dealing with excess water.

Our Conclusion

Safety is the priority when dealing with basement floodwater. Once you understand its cause and can safely enter the area, talk to your insurance company about what remediation services your policy covers. If services aren’t covered, gauge the damage’s intensity to determine whether you should DIY the project or hire a professional.  

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FAQ About Flooded Basement Repair

How do I know if my homeowner’s insurance covers flood damage?

Homeowners insurance typically doesn’t cover flood damage caused by storms or other weather events. Sewage backups are also not covered unless you purchased a specific add-on to your policy. Insurance may cover plumbing issues as long as they weren’t caused by neglect or deferred maintenance. 

How do you get moisture out of a basement after a flood?

The best way to get moisture out of a basement after a flood is to open all the windows and doors, pump out the water, and run fans and dehumidifiers. Starting this process quickly reduces the risk of mold and mildew growth. 

What is a sump pump?

A sump pump is a small piece of equipment that monitors water levels and pumps it out. It has a pipe leading from inside the basement to outside the house, where water drains. You can find electrical sump pumps as well as battery or water-operated pumps.

Is it safe to go in a flooded basement?

Going into a flooded basement is safe if the electricity is turned off and the water level is low. Wear protective clothing, such as rubber boots, gloves, and a face mask, to protect yourself from unsanitary water and potential mold. 

Does a flooded basement cause mold?

Yes, a flooded basement can easily cause mold. Mold colonies can begin to grow within 24–48 hours of flooding. Even if you don’t see mold growth, unhealthy spores could be in the air. 

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