How to Install a French Drain
Prevent water from gathering in unwanted places by installing a French drain to redirect it.
Are you stuck with a spot in the yard where water gathers when it rains? Or maybe you have a planter or gutter drain that leaves an unwanted pool of water. By installing a French drain, you can redirect that water to another spot and keep it from accumulating in one place.
- weed barrier cloth, porous
- drainage rock, about 4 cubic feet for 10' drain
- PVC pipe, at least 2-1/2" diameter
- drill and 3/8" drill bit
- pea gravel, about 4 cubic feet for 10' drain
Before you begin, determine where the problem exists and where you would like to divert the water. This will help determine the length of the trench and PVC and the quantity of other materials needed. To create your French drain with PVC pipe, which is more durable, you will need to create a trench in a straight line. You can create a curved drain with a flexible drain hose, but it will not be as durable and may need to be replaced over time.
Dig a Trench
Dig a trench that is approximately 18 inches deep and at least 12 inches wide. Dig the trench at a slight angle of at least 10 degrees from the starting point to the outlet for the water to flow easily.
Line With Weed Barrier
Line the trench with weed barrier. Be sure to choose a barrier that allows water to pass through. Use the full width of the barrier and allow the excess to lay on the ground outside of the trench. Hold it in place with a few stones or stakes if necessary.
Add Drainage Rock
Spread a layer of drainage rock on the bottom of the trench, about two inches deep. Ensure that the gravel is evenly distributed.
Drill holes through one side of the PVC pipe in a straight line, about one foot apart (Image 1). Turn the PVC pipe about an inch, and drill holes between each of the first row of holes, making them zig-zag about six inches apart (Image 2).
Place PVC Pipe
Lay the PVC pipe in the trench with the holes facing downward and laying directly on the drainage rock (Image 1). Test the pipe by pouring water at the starting point to make sure the angle of the PVC pipe allows the water to flow easily. Cover the PVC pipe with more drainage rock, at least 3-4 inches (Image 2).
Fill Remaining Space
Fold the excess weed barrier over the drainage rock and PVC pipe (Image 1). Fill the remaining space with pea gravel (Image 2). Add decorative stones, pavers or fill the with soil and even replace the grass, if desired (Image 3).