A French drain is is used to remove excess water from low-lying areas that tend to get saturated. These types of drains consist of a trench that is dug and filled with gravel or stone and a top layer of sand. It is inexpensive and easy to install. The first step in installing a surface water French drain is deciding where the system should be located.
Dig a trench in the area of your yard where excess water accumulates. The trench should be from four to six inches wide and up to 12 inches deep.
Create a slope in the trench so that the water will be able to drain away. Check the trench at every two or three feet with a level to make sure there is a consistent slope. Or you can first finish digging the trench and then go back and add loose dirt to create a reasonable slope.
Put a layer of gravel at least four to six inches deep in the trench.
Add a layer of coarse sand on top of the gravel. The sand acts as a filter that only allows water to go down to the gravel. The sand should be at lest three inches thick.
Place a layer of soil on top of the sand to cover the trench. You can then plant grass seed or add sod to complete the project.
Adding a Drainpipe
Place a two- to four-inch layer of gravel in the trench.
Lay a perforated drainpipe on top of the gravel. The pipe should be at least four inches in diameter.
Place a filter fabric, or fabric used to keep weeds out of gardens, over the top of the pipe.
Add another two-inch layer of gravel on top of the drain
Fill in the remainder of the trench with dirt or topsoil.
Things You Will Need
- 4-inch diameter pipe
- Filter fabric
- The length of the trench should be long enough to properly drain water away from a building or other structure. Sand does not need to be added to the trench when using a drainpipe.
- If you don't sand that is coarse (wihout a drainpipe), water may not properly drain through to the gravel. Dirt and mud can clog the drainpipe if you don't use filter fabric.