French drains can be installed both around the foundations or under the basement. The second is usually done when moisture is expected to creep into the house through the basement floor. The pipes laid under the basement capture the water before it reaches the foundation and leads it away.

Should French drain be next to foundation?

French Drains should always be installed around foundations. A French drain takes advantage of gravity and aids in helping ground water seek lower levels away from your home’s foundation.

How close to a foundation can you put a French drain?

We recommend installing the french drains between 2 and 5 feet away from the foundation. There are a few variables that impact the exact distance to dig the new drain lines to carry water away from your home. Finding the right distance: Check where water is pooling naturally during heavy rains.

Where should a French drain be installed in a house?

French drains serve to collect and remove groundwater that would otherwise cause a problem. They’re often used along driveways, in damp areas of a lawn, and around house foundations to help keep the basement or crawlspace dry.

How do you know where to put a French drain?

Plan the Location. Figure out where the excess water is pooling and where you want it to go. When choosing an outlet for runoff water, look for retention ponds or other bodies of water, or tap into existing drainage. You can divert the runoff water to the road curbside if that’s easiest.

Should a French drain be against house?

A French drain should be no deeper than the foundations of a building and, in the case of older buildings, the side of the trench should slope away from the building at no less than 45 degrees. This is to maintain the lateral support of the foundations by the ground surrounding them.

What slope should a French drain have?


A French drain needs a slope to work properly. The slope should descend at a rate of 1%. That rate is equivalent to a 1-foot drop for every 100 feet of French drain. Alternatively, your property may have a natural slope that steeper, and that’s fine.

How deep should a French drain be around a house?

French drain depth: About 8 inches to 2 feet deep should be sufficient for many water-diverting projects, though related systems, such as those built around foundations and sub-ground living spaces, as well as the bases of retaining walls, may be deeper.

Why do French drains fail?

Over time, a French drain may become clogged. Tiny soil and clay granules slip through the pores of the landscape fabric and gradually build up inside the pipe. Another common cause of French drain clogs is root intrusion from grass, shrubs, and trees.

How deep should a 4 inch French drain be?

Depth Recommendations

The minimum depth is typically ​18 to 24 inches​. This depth helps capture most of the water that’s an issue. If your goal is to protect your foundation or keep water from getting into the basement, you want your pipe installed deep enough to achieve that goal.

Does a French drain need an exit?

Short answer to the title of “Where should french drain terminate?” is that, ideally, the french drain will terminate to an above-ground exit on the side of a hill or at least a downwards slope, so that the water that was in the drain can escape to get into the place that normal surface runoff goes from the property.

What is the difference between a French drain and a trench drain?

Aside from what we’ve listed here, the difference between a French drain and a trench drain is that a French drain is used for water that is underground while a trench drain diverts excess water from a surface.

What’s better than a French drain?

If you have a negative sloped yard (which slopes toward your foundation), a surface drainage system is a better choice than a French drain. Sloping of more than 1”-1-1/2” on a 10′ run can result in excessive amounts of water seeping beneath your house.

How do I know if my French drain is working?

Look for Standing Water

If the low areas of your yard are as firm and dry as higher spots, then your French drain is working as expected. Inspect low areas of your yard that are supposed to flow toward the French drain. If the ground is flooded, boggy, or squishy, your French drain is not working.

Which is better French drain or swale?

French drains have a more functional purpose, as they are intended to keep water away from the foundation. Swales, on the other hand, are often recommended by landscapers as a general-purpose drain. Swales are sometimes not an option in urban areas because they require large lots to shape properly.

Can you cover a French drain with dirt?

Can I cover a French drain with dirt? Because a French drain has holes throughout the pipe which allow it collect water, you should not install dirt on top of the drain pipe. Installing dirt will clog the pipe and the holes, rendering it useless.

How do you run a French drain under a driveway?

Quote from Youtube video: We have to cut the concrete. And trench a line all the way down through. And it will discharge there's a small Creek right over there behind that fence.

Do you put gravel under French drain?

The old way of installing French drains is to do it without the gravel and the fabric. Without the gravel and the fabric, however, the drain can clog up with sand and soil over time.

How do you divert water runoff from gravel driveway?

The best way to divert runoff water away from your driveway is to install a French drain or swale. This drain will intercept the water that runs toward your driveway and channel it downhill. With a well-constructed drain, you can stop your driveway from being flooded with runoff.