Yards often have spots that become boggy because of water accumulation. Water runoff destroys flower beds and causes soil erosion. Poor drainage near buildings leads to flooding. Water follows the path of least resistance. It's easier for water to flow through a drain than through soil, so the water will accumulate and flow through the French drain. Redirect the water around a building by using a French drain.
Measure from where the water accumulates to where the water will be dispersed downhill from the problem area. Purchase enough French drain piping plus an extra pipe or two.
Dig a six-inch-deep trench from the problem area to the dispersion area. If the water is being redirected around a building, dig the trench around the building like a shallow moat. The trench should follow a downward path or the trench should get slightly deeper as it approaches the dispersion area. Check the trench with the carpenter's level to maintain the slope.
Fill the trench with two inches of gravel.
Lay the French drain in the trench over the gravel. One end of the French drain piping will be slightly smaller than the other. Attach the ends by placing the narrower end in the wider end. The two rows of holes in the drain should be on the sides of the pipe, not pointing up and down.
Cover the French drain with fabric, which is sold where you bought the drain. The fabric keeps soil and gravel out of the pipe so it doesn't get clogged.
Test the drain by running a hose in the boggy area. The water should accumulate and start flowing through the drain out the opening into the dispersion area. Make adjustments in the slope of the trench if necessary.
Cover the drain with gravel and then sod, grass, or other plantings.