The gravel pictured here (around the building foundation) is very similar to that used in a linear French drain. (Tim Carter)

Q: Water is pouring into my basement now that it’s spring. I’m sick of the water intrusion and the mold it creates. I’ve done so much research online about how to stop the water that my head feels like it’s stuffed with cotton. Can you add some clarity and tell me if you’ve ever solved wet basements and crawl space issues? —Lauren, Lexington, Ky.

A: I’ve solved tens of thousands of wet basement problems. I have my college geology degree to thank for that! I had a focus on hydrogeology, which is the study of groundwater and how it moves.

In my opinion, the best way to solve leaking basements, crawl spaces and soggy soil is to install a linear French drain. This is a simple trench drain in your yard that intercepts the water moving sideways through the soil toward your home. A perforated pipe at the bottom of the narrow trench captures the water and redirects it to the lowest spot on your property.

This trench should be placed about six feet from your foundation and be on the high side of the land that’s sloping toward your home. The trench may be L- or U-shaped. It depends on the direction of the overall slope of the land on your lot. Eventually, the trench daylights on the low spot of your land, and the groundwater flows out of the pipe only to reenter the soil (at a safe distance from your house) on its journey back to the ocean or sea.

The trench has to be only 24 inches deep in most cases because a majority of the water movement through soil is in the top 12 inches, where there’s lots of air. I prefer the solid plastic pipe that has two or three rows of holes drilled in it. The holes always must face downward in the 4 o’clock and 7 o’clock positions.

Never put a sock on the pipe or filter fabric in the trench. Neither are required because silt doesn’t move through the soil. If it did, then spring water would be muddy all the time.

The trench gets filled with rounded or slightly angular gravel that’s the size of large grapes. Water moving through the soil encounters the gravel, falls down to the perforated pipe and uses the pipe to bypass your home.

I’ve created a free downloadable document for you at my website that has a 3-D drawing of this trench drain. The document contains further installation tips. Just go to  to get the PDF.

Tim Carter can call you on the phone free to solve your problem. Go to his website and fill out the form on this page: askthebuilder.com/ask-tim/.