7 Pro Tips: How to Detect a Foundation Leak?

Written By Adam Paul - Waterproofing Expert

Foundation leaks are severe home problems. When a foundation tends to leak it causes severe problems such as mold and mildew growths, musty and odor smell, higher humidity, material degradation, wood rotting, warping and swelling, paint peeling, and wobbling with reducing structural integrity. Before these problems occur you should check the foundation leak to identify and fix them.

Aqviz experts conduct several types of foundation detection methods in our projects. So we include all in this guide step by step with in detail. If you see there is a foundation leak, follow the below steps to detect it.

7 Ways to Detect a Foundation Leak

1. Inspect visually
2. Check gutters and downspout
3. Check plumbings
4. Simulate water exposure
5. Use professional tools
6. Use dehumidifier
7. Monitor foundation cracks

1. Inspect Visually

First, as experts Aqviz recommends you conduct a visual inspection for foundation leaks. You should check both the interior and exterior for water leaking signs.

Interior foundation water leaking signs: Start by examining your basement walls and floors for any visible water damage. Look for water stains, mold, or mildew, which indicate prolonged moisture exposure. Efflorescence chalk is another common sign of water seepage. Also, check for peeling paint or bubbling drywall, which occurs when moisture gets trapped behind surfaces. If your basement has a musty odor, that’s another red flag for hidden moisture issues.

Exterior foundation water leaking signs: Walk around your home and inspect the foundation walls. Look for wider cracks, jagged, or uneven cracks. They often signal water intrusion to the foundation. Pay close attention to the corners and where the foundation meets the ground because these are the weaker areas in the foundation. And  also we suggest you check for damp spots, crumbling mortar, or discoloration, which suggest persistent water exposure.

2. Check Gutters and Drainage

Then you should check foundation leaks due to clogged gutters and drainage. Clogged gutters cause rainwater to overflow and pool around your foundation. So you should regularly clean gutters to remove leaves and debris to prevent clogging. You should extend the downspout at least 6 feet away from the house to prevent water from saturating the soil near the foundation.

Next, Aqviz experts pay attention to the ground slope (grading of the slope). Because if grading is lower, or towards to the foundation, water can accumulate over time. This may cause severe water problems in the basement. So you had better have a slope away from the foundation at a rate of 6 inches over 10 feet. We recommend you add some soil to change the grading away from the foundation. If you can’t control the grading we recommend you install a French drain to redirect water and reduce foundation water pressure.

3. Check Plumbings

Next, we recommend you check for plumbing leaks. This is how we do this in our project. First, you had better turn off all water sources in your home, including faucets, appliances, and irrigation systems. Then, observe the water meter if it continues to move, it indicates an unseen leak that could be affecting your foundation. Address any leaks promptly to prevent water infiltration.

As well as we suggest you conduct a toilet leak check and a drain and sewer leak check as follows.

Toilet leak check: Add a few drops of food coloring to your toilet tank and wait 15-30 minutes without flushing. If the color appears in the foundation area, there’s a leak in the toilet system that could be contributing to foundation moisture issues.

Drain & sewer leak check: Pour colored water (using food dye) into sinks, tubs, or floor drains near your foundation. If you notice the dye seeping into basement drains, floor cracks, or foundation walls, it could indicate a leak in your plumbing or sewer line. 

4. Simulate Water Exposure

If you can’t imagine the source of the foundation leak we suggest you do this.

Simulate heavy rain by running a garden hose around the foundation for 10-15 minutes. Then focus on areas where water might collect, such as foundation corners or where downspouts discharge. Then, check the basement or crawl space for signs of moisture intrusion. 

5. Use Professional Tools

Until this, if you can’t detect the foundation leak, we suggest you to use the below tools.

Use a moisture meter: A moisture meter helps detect dampness in walls and floors. Press the meter against suspect areas, especially near cracks or water stains, to check for elevated moisture levels that might not yet be visible.

Use infrared cameras: IR cameras detect temperature differences. It reveals hidden leaks behind walls or beneath floors. You can rent one or hire a professional to conduct a thermal scan of your foundation.

6. Use a Dehumidifier

You can detect foundation leaks by using a dehumidifier. If your basement is highly humid and using a humidifier can control this within a few days it can be a sign of a foundation leak. As well as you can see mold and mildew growth, and other water damage in the foundation due to higher moisture conditions. 

7. Track the Foundation Cracks

Our experts take some time to do this test. Sometimes it can be months. So it is crack tracking and glass shared test.

Crack tracking: Mark the width of foundation cracks with a pencil and note the date to monitor any expansion. If cracks widen over time, it may signal ongoing water infiltration or structural movement.

Glass shared test: Tape a small glass shard over the crack. If the glass breaks, it confirms that the crack is actively growing, indicating a deeper foundation problem that requires professional evaluation.

Both of these indicate that crack width is changing over time. So cracks can be a reason for the foundation leaks.

How to Prevent Foundation Leak?

If you observe any water leak from the foundation you can prevent it by following the below steps.

1. Manage water drainage: You should keep the gutters and downspouts clean, maintain a ground slope properly, and install a drain system around the foundation.
2. Waterproof the foundation: You can waterproof the interior and exterior foundation walls. Foundation waterproofing helps you to seal all the cracks in the foundation surface.
3. Avoid planting near the foundation: You should avoid plants near the foundation, keep plants at least 3-5 feet away. This helps to protect the foundation from the root.
4. Maintain plumbing properly: Inspect pipes and plumbing near the foundation and repair them once needed.
5. Fix foundation cracks immediately: If you observe foundation cracks you should fix them immediately to prevent water leaks.
6. Do regular foundation inspection: You should conduct regular foundation inspection check for leaks. 
7. Maintain soil moisture at the foundation: You should not overwater near the foundation. You should use a soaker hose to maintain a consistent moisture level in the foundation.