Imagine walking downstairs and seeing your basement filled with water and your precious possessions floating around… It’s not something anyone wants to ever experience, but unfortunately, it’s something that many Americans deal with each rainy season.

A flooded basement can cost you thousands (maybe more), and it’s not just in lost belongings. Flooding can cause damage to your walls and floor and also lead to mold, mildew, and other health hazards.

Sometimes flooding is a one-time occurrence. Oftentimes, it is more frequent. Knowing the triggers of flooding can help you take steps to keep your basement dry and your possessions safe. Here are the common causes of a flooded basement. Pro Tip – You can help protect against many of them with flood insurance.

1. Location

Your location is one of the key reasons that your home floods. You may live in a low-lying area prone to flash floods. Your home may sit at the bottom of a hill, drawing precipitation toward it. If the land around your home is sloped down toward it, there could be a risk of your basement flooding. Take a critical look at your property. Look for depressions or standing water around your home, in the ground, or with pavement that has settled or deteriorated. These are areas that you will want to address.

What you can do: Fill the depressions in the ground with a mound of soil to create a slope away from your home. Use clay-based rather than sandy soil, as it will help to repel the water. Remove and/or replace pavement, and again, slope it away from your home. If a hill next to your house is causing the problem, a civil engineer may be able to provide some guidance.


2. Weatherproofing

During construction, your home’s foundation, and your basement’s walls and floor, should have received a coating of sealant to keep water out. However, sealants can deteriorate over time, allowing surface water to leak in. Surface water also can pool around your home due to the location and settings of your lawn irrigation system. Both of these issues are relatively simple to fix.

What you can do: Avoid placing irrigation next to the house, or limit water dispersed there. Make sure your irrigation system does not turn on when there has been plenty of rain. You also can take steps to reseal your basement. Use a polyurethane caulk designed for masonry to seal any cracks or gaps that are larger than 1/8 inch wide. (For finished basements, consult your local hardware store for options.) Then apply a waterproof coating to your basement’s walls and floor. You also can use waterproof paint.


3. Groundwater

If surface water is not the issue, groundwater might be. Underground pressure can push the water into your basement through cracks or holes. If you notice water coming up through the concrete floor, or coming in from multiple points, this could indicate groundwater.

What you can do: A perimeter drain system can help. Such systems relieve the pressure and use gravity to pull the water to the sides and down. They can be installed above or below the slab. An under-floor system may be better but it is more expensive. It requires some of the concrete floor to be removed in order to install the drainage pipes. If you already have a drainage system, such as drain tile or weeping tile, and you are still seeing water or moisture, it’s possible that you need to replace it. Those systems may degrade over time.


4. Clogged Gutters and Downspouts

It’s not unusual for gutters to be clogged with leaves and other debris. This prevents them from effectively doing their job, which is draining the water into a downspout and away from your home. Improperly positioned or broken downspouts also contribute to the problem. Water that drains too close to your house not only can create flooding; it can erode soil which can lead to further problems.

What you can do: Clean your gutters a few times a year. Install a gutter guard to reduce future clogs. Make sure your downspout drains far enough from the wall, at least 5-6 feet. Some experts suggest as much as 10 feet.


5. Plumbing Leaks

If you notice a large amount of water quickly, it could be a plumbing leak. Broken, cracked, and clogged pipes can cause this type of emergency. During winter months, water freezes and expands, sometimes bursting pipes. All of these issues can cause your basement to flood.

What you can do: Most likely, your pipes have to be replaced. Call your plumber to repair the issue as soon as possible.


6. Sump Pump Failure

You may have a sump pump installed, a device that collects excess water and drains it outside your home. A sump pump is powered by electricity, and therefore only works when there is power. Consider buying a sump pump with backup battery power to avoid any interruptions. If your sump pump fails because of lack of power, or because it is not working properly, that could cause your basement to flood.

What you can do: Regular inspection, cleaning, and testing your sump pump can help. Consider an add-on to your homeowner’s insurance of sump pump discharge or overflow coverage. This can help cover the costs of repair and replacement in the event of a sump pump failure.


7. Sewer Backup

Heavy rain can sometimes back up the municipal sewer system. Sewer backups also may occur due to sewer lines that are clogged with waste, tree roots, or other debris. When these things happen, flooding in your basement can occur, and the results will, at minimum, be smelly.

What you can do: If your basement is flooded with sewage, get professional help to clean it. You also will likely need to get the local government involved. Finally, you can install backflow preventers to help keep the sewage out of your house.

If your basement does flood, know that an insurance policy can help cover the costs. Many people don’t realize that a traditional homeowner’s insurance does not cover floods. For that, you will need a separate policy. If you’re in a flood zone, you will want that extra insurance.

There is a 30-day waiting period to buy flood insurance, so with the rainy season upon us don’t wait until the last minute!


This article is furnished by California Casualty, providing auto and home insurance to educators, law enforcement officers, firefighters, and nurses. Get a quote at 1.866.704.8614 or


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