flooded basement

Here’s Why Your Basement Walls Leak When It Rains

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If your house is built over a basement, you may dread every rainstorm that rolls in. Basement walls that leak when it rains are very common and can be frustrating to fix. From where you stand, it may seem like the water is seeping in from nowhere.

If your basement walls leak when it rains, there are some steps you can take to fix the problem. Read on to discover some possible causes and how to fix them.

Hydrostatic Pressure

One of the biggest reasons basement walls leak when it rains is something called hydrostatic pressure. This is basically the idea that water wants to reach a point where it’s spread in an even layer over everything. It will push through whatever’s in its way until it reaches an equal pressure level everywhere.

When it rains, the water pressure outside your basement walls goes up. There’s more water in the ground than in your basement, so that water begins to seep through your basement walls and floors. It worms its way through the cracks and crevices until it reaches an equal pressure and you have a puddle in your basement.

Loose Soil Around Your Foundation

One factor that may be contributing to that higher hydrostatic pressure is loose soil around your basement. The looser the soil, the more water it can absorb and the higher that hydrostatic pressure becomes. To understand how this works, think about pouring water over a piece of bread versus a piece of Styrofoam.

In bread, there are a lot of air pockets that can absorb water, whereas Styrofoam is more densely packed. It doesn’t take long for bread to absorb water or for that water to start leeching out of it into the surrounding area. But because most of the water would run off the top of the Styrofoam, it would take a lot longer before Styrofoam starts to get soaked or leak.

Leaky Window Wells 

If hydrostatic pressure isn’t the issue, you may have a leak somewhere in your basement. Oftentimes, window wells are the culprit for leaky areas. If a window well isn’t installed or sealed the correct way, they can become a funnel inviting water into your house.

The easiest way to tell if you have a window leaking is to look at where the water is pooling in your basement. If it’s on the opposite side of the room from any windows, you probably have another culprit at work. But if puddles always seem to show up near your windows, check the wells for evidence of leakage, including discolorations, damp spots, or worn spots.


Depending on the geography around your home, the water in your basement may be coming from plain old flooding. The basement is the low point in the home, and those are susceptible to flooding if water tends to pool in your yard. The majority of flooding risks have to do with soil composition and drainage solutions around your home.

If your soil is mostly rock or clay, you may be more susceptible to flooding since water runs off the top of it. While this runoff quality is desirable in the soil around your home, you don’t want that in the rest of the yard or the water may just as easily run off into your house. Even if your soil quality is good, if you live somewhere close to sea level and don’t have good drainage solutions, you may also find yourself the victim of flooding.

Damage It Can Cause

If you have a finished basement, we don’t need to tell you the damage basement leakage can cause. The costs of maintaining or replacing carpets alone can run you out of house and home. But if you have an unfinished basement, it may seem like little more than an inconvenience to have a wet basement.

In addition to making that space in your house unusable, unwanted water in your home can be dangerous. Mold can start to grow, posing a health hazard for people who are immunocompromised or have asthma. And if the water gets to your electrical systems, it can cause serious damage that could injure you or your family. 

How to Stop Your Basement Leaking

Trying to stop your basement leaking is a tricky prospect that will involve a lot of trial and error. The first place to start is with obvious risks: check your windows, doors, and walls to see if there are any areas that are obviously leaking. If you find any, patch those up as thoroughly as you can.

If the problem has to do with hydrostatic pressure, one place to start is to improve the drainage systems around your home. Make sure your gutters are in good working order, install drains as needed around your property, and make sure all land around your home slopes away from the house. This can help to prevent some of the water buildup around your basement walls and reduce basement leakage. 

Reducing Basement Moisture

Even after you stop the leaks, your basement may still be a pretty damp place. A combination of condensation and general groundwater leaves your basement feeling muggy even if there aren’t puddles of standing water around. There are some additional steps you can take to reduce the moisture levels in your basement to something more reasonable.

The first step to reducing your basement moisture levels is to get a dehumidifier. You can buy dehumidifiers designed to work in basements and that have sump pump installation options and drains so you don’t have to empty water tanks all the time. You can also insulate your walls and install fans to help keep condensation under control.

Learn Why Your Basement Walls Leak When It Rains

Trying to figure out why your basement walls leak when it rains can be frustrating. The first thing to check is your windows, and if those aren’t the culprit, move on to checking drainage systems around your home. If you can improve your drainage by even a little, it can go a long way to reducing the water in your basement.

If you’d like to learn more about how to improve your home, check out the rest of our site. We have consumer advice and market outlooks to help you make the best decisions for your house. Check out our homeowner’s advice to learn the smart way to improve your home today.

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