What Is Causing My Basement To Leak? (10 Potential Reasons)

Ben Kissam
Written by Ben Kissam
Updated December 13, 2021
Basement area with staircase
Photo: Javani LLC / Adobe Stock


  • Water accumulation around your foundation is a major cause of basement leaks

  • Keep gutters clean and downspouts pointed away from your home as a preventative measure

  • It’s a good idea to install a sump pump if your basement has flooded before

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Discovering water in your basement is certainly disheartening, especially if yours is finished or water found its way into some prized belongings you had in storage. Besides having your basement restored by a water damage professional, it’s important to look at what underlying issue may have caused it to leak or flood.

Learn 10 of the common causes for water in your basement below, as well as ideas for how to prevent yours from leaking.

1. Pressure Created By Soil Around Your Foundation

Water damage in basement
Photo: cunaplus - Adobe Stock

Lateral hydrostatic pressure—essentially, force created from water moving in a horizontal direction— created by the soil surrounding your home is one of the leading causes of leaky basements. The soil directly around your basement walls and floor can absorb water and expand or shift over time, putting excess pressure on your foundation. 

Water weighs 60 lbs per cubic foot. So after an intense rainstorm, for example, there could be tens of thousands of pounds of pressure on your walls, potentially leading to cracks, leaks, and water coming up through the basement floor.

2. Cracks In Basement Walls or Floor

Cracks that allow water to seep into your basement will result in pressure buildup. The most vulnerable areas of your wall or floor are next to breaks in concrete (near window wells, for example) or long areas where there is no turn (i.e., the middle of the wall).

Depending on the severity of a crack in your foundation, a number of remedies are possible. Applying sealants can fix minor issues, but steel beams and other reinforcement methods may be necessary for serious damage.

3. Overflowing Gutters

We’ve all heard how important it is to keep our gutters free of leaves and debris. Ineffective or clogged gutters can, you guessed it, lead to water buildup, which then seeps into the soil directly surrounding the foundation. Again, this pressure can build up and lead to cracks that cause leaks in the basement.

4. Your Downspouts Are Too Short

If you suspect your gutter drainage system is to blame for water in your basement, but you’ve already cleaned them out, move on to troubleshooting your downspouts.

A gutter installation professional typically installs gutters at a slope to channel water in your downspouts, which then channels the water into areas of your lawn away from your foundation. Most pros recommend they be laid at least six feet from your foundation. Otherwise, that water could be settling around your basement.

5. Settled Pavement

Pavement, unlike soil, does not absorb water. However, your driveway or patio pavement can settle over time, leaving it at an angle that channels water back towards your home.

To fix this, a local driveway paving company can remove old asphalt and/or install a new driveway. A more budget-friendly option is to remove things like weeds that have popped through the driveway and fill holes or patches to prevent water backflow.

6. Ineffective Grading

Poor grading means that your home’s lawn (or objects in it, like the driveway or downspouts) are channeling water back toward your home. If you have lots of standing puddles after a rainstorm, this could be a sign of ineffective lawn grading.

Or, your yard could be the issue. If so, try adding dirt to poorly sloped areas. The average cost to regrade a yard is around $15 per cubic yard.

7. A Leaky Roof

You’re probably noticing a pattern by now, even though this next one might surprise you. When water accumulates in and around your foundation, troubles with leaks arise. And yes, even a damaged or old roof that’s leaking water can be the culprit that causes your basement to accumulate water, too.

8. Poor Or Absent Subfloor Drainage System

Basement drainage systems like sump pumps or french drains help remove water and reduce pressure from building up around your foundation. 

It’s a good idea to install a new sump pump if you live in an area with a rainy season or if your home has flooded before. Installing one of these devices costs $1,255 on average.

9. Condensation Buildup

In the same way condensation builds up on a bottle of beer or a can of soda, warm weather applied to a cool basement wall can lead to condensation—almost as if your basement walls are sweating. Too much condensation can lead to wet spots or puddles inside your home.

10. Damaged Window Wells

The purpose of a window well is to keep soil (and pressure built up from rainwater in the soil) from directly coming in contact with breaks in the foundation, which tend to be the most vulnerable parts.

Basements can easily leak when window wells become rusted, broken, or have holes or cracks. These can be reinforced with sealant or by replacing an old window well, both of which will help prevent basement leaks in the future.

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