How to Make Your Own French Drainpipe

Dig a trench where you want the water to drain. It needs to be approximately 6 inches wide. The depth will vary because you will need to slope it to move the water. Start out with a trench that's 6 inches deep to accommodate the gravel and pipe. Dig feeder trenches as well if there is a large wet area. Have these trenches run to the main trench.

Use a 4-foot-long level to help you gauge the slope. The slope needs to be approximately a 1/16-inch drop for every 6 feet. Raise one end of the level to a little less than 1/16 inch and note where the bubble is. Lay the level in the trench and dig the trench out as you go so that the bubble stays at the sloped mark.

Fill the trenches with an inch of gravel to create the base.

Place the level back in the trench to make sure the slope is maintained. Adjust the slope by adding or removing gravel.

Place perforated 4-inch-diameter drainpipes in the trench with the holes facing down. The water seeps into the holes from underneath and runs down the pipe. The gravel takes up a good portion of the drain water and allows it to run down the trench. The pipe is there to move excess water away quickly.

Cover the pipe with another inch of gravel. Layer over the top with a thin coat of sand and topsoil. Sprinkle grass seed on the dirt and cover it with another thin layer of dirt if the trench is located in a lawn. You can save yourself from having to plant grass seed if you set the top layer of sod aside to be put back later.