How to Build a French Drain

A French drain is a sloping trench that is capable of draining water from one place to another. If you have an area that is always wet and practically useless, it’s a good idea to try and build a French drain.

Required tools and Materials

Line level
Landscape cloth
Two stakes

Step 1

Determine where you want the drain to culminate. You can choose a sandy soil far from home or a storm drain for example.

Step 2

Consult the local building code before you start. Next, pick the route. The ideal one is by a slope close to your property’s edge. Avoid areas with tree roots and other possible hindrances.

Step 3

Dig up a trench 4 times as deep as your pipe diameter. Make it six inches wide. Put a couple of inches of coarse gravel. Set the pipe on the trench. The slots must be pointed down.

Step 4

In order to build a French drain, hide the pipe with landscape cloth. Conceal all of it with gravel. Tip it off with sand. Put some top soil in the trench. Fill it up and then seed it.

Getting the Slopes Right

Step 1

Put a stake in the surface. It should be set at the uphill and the area where you plan to excavate the trench. Tie a string on its end.

Step 2

Head to the end of your proposed trench. Put another stake in. Tie this to the string, but loosely.

Step 3

Utilize the string level to make sure the string on the stakes is level. Mark the location of the string on the 2nd stake.

Step 4

Measure an inch per 100 feet of the length of the trench on the stake’s bottom. Note the location. Fasten the string permanently.

Step 5

When you dig the trench, keep measuring the distance between the trench bottom and the string. Make sure that it is the same. As long as the distance is the same, your slope will be consistent and true.

Tips and Warnings

If the water problem isn’t too bad, you can make the French drain without putting in a plastic pipe. Just make the trench and put in the gravel, sand and topsoil. But if the water problem is extensive,
the pipe will be necessary.

As this guide shows, it is not that difficult to build a French drain. While it is very easy, you need to make sure the water does not enter into your neighbor’s property.

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