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How To Stop Basement Flooding: Step-by-Step Guide

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Default Author Icon Written by Angela Bunt Updated 04/10/2024

Basements can be hard to keep dry. Heavy rainfall or burst pipes combined with poor drainage can flood a basement quickly, causing water damage. Since a basement or crawl space serves as a home’s foundation, flooding can ultimately cause structural damage that seriously affects the house’s stability. Damp spaces can also grow mold and attract pests, putting your health at risk.

Our guide explains how to waterproof a basement to prevent flooding and what to do if your basement has already flooded.

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How Can You Prevent Basement Flooding?

You can keep water out of your basement by carefully inspecting your home’s drainage system and fixing any problems before the next rainstorm. Here’s how to quickly address common causes of basement water:

  • Clean your gutters. Remove leaves, dirt, and other debris at least once a year to ensure water flows freely.
  • Extend the downspouts. Install downspout extensions as needed to ensure your gutters direct water at least 4–6 feet away from your foundation. Alternatively, you can install rain barrels or a dry well to collect the water.
  • Look for foundation cracks. You can fill small, vertical cracks with epoxy or hydraulic cement. Larger or horizontal cracks need professional attention, as they could be signs of serious damage.
  • Waterproof porous walls. Even if you can’t see cracks in your basement walls, groundwater can still seep through porous concrete. If you suspect this is happening, apply waterproof paint to seal foundation walls and research other solutions.
  • Seal around windows and doors. Use caulk or expanding foam to close any gaps around basement windows and doors. If your basement has egress windows, ensure the window wells have functioning covers or drains.
  • Invest in an indoor drainage system. Often, this consists of installing a sump pump inside a pit beneath a floor drain. You may also need a series of French drains around the basement floor to collect water. Make sure the pump has a battery backup for power outages.
  • Check your sewer lines. Have a plumber inspect your home’s sewer biennially, especially if you have older pipes or trees nearby. Consider installing a backwater valve in case the city sewer system becomes overloaded.
  • Monitor your water meter. Check for hidden leaks by taking a meter reading and then not using water for a few hours. A change in the reading could indicate a leak, including those underground near the foundation.
  • Inspect appliance connections. Look for leaks in the drain pipes connected to washing machines and dishwashers. Consider smart water leak detectors for these appliances.
  • Grade your yard for drainage. Ensure the ground around your home slopes away from the foundation. You may be able to handle small regrading projects with a shovel, but larger projects will require heavy machinery or landscaping professionals.
  • Install French drains. If water continues to pool near your foundation, install a French drain. This perforated pipe, surrounded by gravel, will redirect water away from your home’s foundation.
  • Plant strategically. Shrubs and water-loving plants near downspouts can help absorb water and divert it from your home.
  • Consult a waterproofing expert. If basement water is a recurring problem, you may need to invest in a more extensive solution. A qualified basement waterproofing professional can install vapor barriers, create active drainage systems, or even wrap the foundation in a waterproof membrane to keep the basement dry.
  • Prepare for the worst. Regularly test your sump pump to ensure it’s ready for an emergency, and install leak detection devices to alert you to problems quickly. Review your homeowners insurance to see if it covers flood damage and consider upgrading if it doesn’t.

Check out the video below to learn more about ways to prevent your basement from flooding. Damage-prevention specialist Michael Millegan highlights different types of sump pumps and water leak detection systems, including water-powered sump pumps that continue working even during a power outage.

How Do You Fix Basement Flooding?

Unfortunately, even the most thorough prevention might not keep all water out of your basement. If the worst happens, you need to act quickly to minimize damage and health hazards.

Note: If the water is deep or you suspect electrical issues, do not enter the basement. Call an electrician or emergency services.

Steps to follow

Here’s what to do if your basement floods:

Shut off the electricity and gas to prevent electrocution and suffocation. If you can’t safely reach the breaker box, call an electrician immediately.

Put on boots, gloves, and a mask before working in a flooded basement. You may also need hip waders if the water level is above your boots.

Find out where the water is coming from, whether it’s stormwater, burst pipes, a leak, or sewer backup. Turn off your home’s water if the problem is a leak or burst pipe.

Take pictures with your phone or digital camera to document the damage for insurance or home warranty claims.

Clear existing drains or use a wet/dry shop vac to remove the water. If all else fails, you can use mops, buckets, and towels.

After you have removed as much water as possible, open doors and windows for ventilation.

Dispose of porous water-damaged materials, such as drywall and carpet, before they begin to grow mold or mildew. Move salvageable items to a dry, well-ventilated area.

Thoroughly dry the basement with fans and dehumidifiers. Once dry, clean all surfaces thoroughly with disinfectant and apply anti-mold spray.

Contact your home warranty company (if applicable) and your homeowners insurance company to initiate claims for covered damage.

For extensive flooding or sewage contamination, call in specialists for safe and thorough cleanup.

How To Hire a Pro

While you’ll likely need a professional to help repair your flooded basement, you can also hire a waterproofing contractor for flood damage prevention. Who you hire depends on the problem:

  • Plumbers can replace burst pipes and fix internal leaks.
  • Electricians can check for electrical damage and handle any rewiring.
  • Structural engineers can assess foundation damage and determine if structural repairs are needed.
  • Waterproofing specialists offer a range of preventative solutions, including exterior waterproofing and advanced drainage systems.
  • Foundation repair specialists can fix cracks, leaks, or other issues in your foundation.
  • General contractors can oversee projects involving multiple trades.

Regardless of who you need to hire, here are a few things to consider as you search for a qualified professional:

Anyone you hire should be properly licensed, bonded, and insured to carry out the work you need. All states require plumbers and electricians to have a special license. Other contractors, such as waterproofing and water damage experts, don’t typically need a specific license, but check with your state.

If you file an insurance claim after a flood, your insurer can be a valuable resource. They may have a list of preferred contractors or restoration specialists familiar with their claim process. They might even pay contractors directly, simplifying the process for you. Your agent will walk you through specific documentation requirements and explain coverage limits.

Look at the company’s Better Business Bureau page, along with customer review sites like Trustpilot and Google Reviews. Friends, neighbors, realtors, or even your home inspector might have great contractor recommendations, too.

If it’s not an emergency, get quotes from at least three local contractors to better understand prices in your region and find the best deal.

Our Conclusion

Preventing basement flooding is all about sealing leaks and ensuring proper drainage so water flows away from your foundation. You can take many steps on your own, but if you live somewhere with a high water table or lots of precipitation, you may want to call in professionals. Basement waterproofing costs are often lower than repairing water damage or foundation repair prices.

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FAQ About Basement Flooding

What is the average cost of basement waterproofing?

Basement waterproofing costs $5–$10* per square foot, so a 1,000-square-foot basement will cost $5,000–$10,000. Most homeowners pay between $2,000 and $8,000.

* Cost data sourced from contractor estimates used by Angi.

How do I know if my basement has water damage?

Here are some signs that your basement has a moisture problem:

  • Visible water stains on the walls, floors, or ceiling
  • Bubbling, flaking, or peeling paint
  • Damp or rotting wood
  • Efflorescence (white mineral stain) on concrete floors or walls
  • Mold or mildew
  • Musty or stale odors
  • Puddles or standing water
  • Foundation cracks

Should you let a flooded basement dry on its own?

No, you shouldn’t let a flooded basement dry on its own. Improper drying could lead to mold growth, weakened foundations, or other physical damage to your home. Remove excess water immediately and dry the area with humidifiers or fans.

Why does my basement flood during heavy rain?

Your basement floods during heavy rain because excess water that your yard can’t absorb puts pressure on your basement walls. The water then seeps inside through cracks or porous concrete. Downspouts that don’t extend far enough from your home, clogged gutters, and overflowing sewer systems can all contribute to basement flooding.

How do I keep rain water out of my basement?

To keep rainwater out of your basement, make sure your gutters and downspouts direct water several feet away from your foundation. Inspect your foundation for cracks and consider waterproofing it. Finally, make sure the ground slopes away from your home to encourage proper drainage.

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