Wet Basement Causes and Solutions

Wet or damp basements can occur in both old and new homes, and it's critical to address the problem quickly. The most common methods of preventing basement water problems are to waterproof the walls and add drainage features, such as drain tile and a sump pump to eliminate water that collects in the basement, which can be expensive fixes.

The good news is the source of the water often is on the outside of the home, above the ground, and easily remedied. 

In addition to tips on getting your basement dry, learn common reasons for water leaking inside and what to do about it.

What to Do Immediately If You Have Water in Your Basement

• Proceed with caution. If the water level is high enough to cover electrical outlets or pose any threat of electrocution or fire, cut the power off to the basement. If the electrical panel is in the flooded area, call an electrician or your utility company to have them safely shut the basement power off.
• Determine the water source and stop the leak, if possible. If a broken pipe, plumbing leak, or appliance or fixture hooked up to a water line is flooding your basement, shut off the water supply to stop the flow. If the source is heavy rain, you may have to wait out the storm before water removal and cleanup can proceed. If the leak is from exterior sources, you may not stop water from coming in until a bigger fix is made.
• Dry out your basement. The amount of water in your basement may determine whether drying out your basement is a DIY job or one for a professional. If there's less than a foot of water, you can use a mop, a wet-dry vacuum, or a submersible sump pump to remove standing water. If there's more than a foot of water, call a water mitigation professional to pump the water out quickly and safely. Either way, water should be removed as soon as possible and the basement needs to be dried out to prevent damage to your home and mold growth.

Why Does My Basement Get Wet? Common Causes and Solutions

Check the Landscape Grade

Cause

When homes are constructed, the areas around the foundation are often backfilled with loose soil. And this backfill can settle more than the surrounding undisturbed soil. Over time, the backfill compresses, creating a slope (grade) that angles downward toward the foundation. These low spots near the foundation can cause water to drain toward the house and pool against the foundation, where it seeks entrance through cracks.

Solution

Walk around the entire house with a critical eye, making sure the grade (dirt or lawn) slopes away from your foundation and basement walls. The ground should slope away from the foundation with a vertical drop of about 8 inches for the first 2 feet of horizontal distance from the foundation wall. Regrading the soil around a foundation remedies the problem in many situations. This can involve trucking in substantial amounts of soil to reverse the direction of the slope.

Check the Slope of Patios and Walkways

Cause

Patios and walkways made of concrete or brick pavers might also contribute to the wet basement problem if they improperly slope toward the house. Correctly constructed paved surfaces should slope away from the foundation by a pitch of at least 1/4 inch per horizontal foot of distance.

Large patios are sometimes built with a slight funnel shape, so rain water flows toward the center and into a drain there. The drain sometimes is connected to an underground perforated drain pipe that leads out to the lawn, possibly with a pop-up relief valve. But it is not uncommon for improper construction or soil settling to cause a patio to develop a slope toward the foundation.

Solution

This can be a difficult problem to correct. Solid concrete slabs, if they are small enough, can sometimes be mud-jacked to change their pitch to slope away from the foundation. Brick paver patios and walkways can be disassembled for the base to be regraded to the proper slope and then reassembled. 

It also might be possible to create a small curb or dam along the edge of the patio or walkway where it adjoins the house. This combined with good sealing of the paved surface, can help to direct water laterally away from the house rather than allowing it to drain downward along the side of the foundation wall. 

Where such solutions are not practical, you can minimize the problem by making sure that the roofline above the patio is equipped with good roof gutters and downspouts that direct water away from the patio and foundation. 

Check the Driveway Slope

Cause

Paved driveways that slope toward the house can also direct water against the foundation, where it drains downward and seeks entry into the basement. Driveway slabs sometimes develop sunken areas near roof gutter downspouts. And the large, flat surface of a driveway can carry a lot of water, so checking its drainage is important. 

This problem is especially prevalent in neighborhoods where the lots are narrow and adjoining neighbors share a common driveway that touches both foundations. Each rainstorm will dump water from both roofs onto the driveway.

Solution

If your driveway is draining into your house, one solution might be to have a concrete contractor pour a small curb up against your house where the driveway abuts it. This way, the water will be directed against the curb and flow down the driveway and into the street, rather than against your foundation or basement wall.

Check Roof Downspout Discharge

Cause

The problem of improper drainage outside the home can be made much worse by an improper discharge of the roof gutter downspouts. Roof downspouts can add a literal flood of water to areas prone to drainage problems. A 1,500-square-foot roof will shed around 940 gallons of water in a 1-inch rainstorm. If you assume that water will flow out of an average of four downspouts, you might have as much as 235 gallons of water pouring out of one downspout.

Downspouts often dump water right at the base of the foundation. Or they might be constructed to channel water through a vertical drainpipe along the foundation wall to the footing drain system and sump pump. But the vast amounts of water flowing off a roof can easily overwhelm such systems. 

Solution

The best solution here is to equip downspouts with long horizontal extensions that channel roof water away from the foundation and into an area of the yard where the water is absorbed or directed away from the house. Also, make sure the gutters are clean and flowing properly.

Check Your Neighbor's Runoff

Cause

Another common source of problems, especially with small lots where the houses are close together, is water being directed toward your house from a neighbor's property. This often results from poor landscape grading on the neighbor's property or a roofline, roof gutter system, or downspout extension that directs water toward your home. It's also fairly common for new construction on a neighboring property to cause water problems for adjoining homes because it changes the way the water had been draining. 

Solution

Most neighbors will take measures to correct the problem if you diplomatically draw attention to the issue. If reluctant, they also can be legally compelled to fix the problem if they are in violation of area codes.

One solution for water runoff problems is called a French drain system. This is a landscape project in which a gravel-filled trench helps to direct water in the direction you want. When combined with landscape grading that directs water away from the foundation and toward the French drain, it is a very effective method. A French drain system installed on the property line between two closely adjoined houses can help relieve water problems for both homes. Friendly neighbors might even be willing to share the cost of installing such a system. 

Check for Subsurface Groundwater

Cause

When there is too much water in the ground near a wall or basement floor, it can start to come through small cracks. Subsurface groundwater is part of the natural water cycle. It comes from precipitation that infiltrates under the ground. Groundwater can flood or start to seep through cracks in the floor when it is overly saturated, like after weeks or even months of heavy and prolonged rainfall.

Solution

To prevent subsurface groundwater from entering your basement, take care to repair any cracks in your foundation or floor. Make sure your floor slopes toward the drain in your basement floor as well. If you live somewhere prone to heavy rains, you may also want to consider installing a drain tile or sump pump, which can help with the removal of excess groundwater. Finally, you could opt to waterproof your foundation wall. Hire a professional to install a waterproof barrier around it, which will aid in keeping water out.

When to Call a Professional

You may need to hire a professional if you need help identifying how water is getting into your basement and solutions to fix it. For issues with landscape grades and slopes, downspouts and gutters, foundation repairs, or for an overall assessment, call a general contractor with waterproofing experience or a basement waterproofing contractor. Seek a licensed plumber for broken pipes or to install a sump pump. For major floods, a water mitigation company can remove water and dry out a basement. Once it's dried out, a water damage restoration company can rebuild a flood-damaged basement to its original condition.