How to Install an Outdoor Drainage System

How to Install Outdoor Drainage System

Many yards have low spots that fill with water. Sometimes a new patio or walk will actually create the problem: water doesn't soak through the new surface, running into the yard and puddling instead. Seepage trenches will solve the problem. Dig a trench at the low point of the problem area, line it with either flexible or rigid drainpipe, and channel the water away from the house and away from the neighbours. If you have nowhere to divert the water, run the pipe filled with stone. The water will collect there and percolate into the ground.

Skill Level: Intermediate
  1. Step 1 Dig a Trench for the Pipe

    Dig a 2-foot-wide trench about 6 inches deep for the pipe along the entire length of the low edge of the trouble spot. Continue in a straight line to a point where the pipe can exit the ground or to where you’ll dig for the dry well.

  2. Step 2 Slope the Bottom of the Trench

    Dig to create a slope of 1/8-inch for every foot of trench length. To gauge the slope, slip a 1/2-inch spacer between a 4-foot level and a straight 2x4 that is at least 4 feet long. When the bubble in the level is centred, you have the right slope.

  3. Step 3 Dig the Dry Well

    If the water will drain into a dry well, pick a spot in line with the ditch you're digging, at least 10 feet away and downhill from the house. Dig a hole 2 to 4 feet wide and about 3 feet deep. Make sure to avoid buried cables or utility lines. If you suspect that surprises lurk underground, call local authorities and have them flag locations.

  4. Step 4 Put in Gravel and a Drainage Pipe

    Shovel in enough gravel to cover the bottom of the trench. Lay 4-inch-diameter drainpipe along the bottom of the trench. (With rigid pipe, which has a single row of holes, lay the holes facing down). Continue running pipe to where the pipe leaves the ground or a few inches into the dry well. If you need to connect lengths of pipe, do it with fittings and without glue.

  5. Step 5 Line Each Side of the Dry Well With Landscape Fabric

    If the water is to drain into a dry well, line the well with landscape fabric, using a large enough piece to extend over the top layer of gravel. The landscape fabric keeps soil from mixing with the gravel. Cut a hole in the landscape fabric for the drainpipe.

  6. Step 6 Cover the Pipe With Gravel

    Shovel enough gravel into the trench to cover the pipe. Lay landscape fabric over the gravel. Fill the rest of the trench with soil and cover the soil with sod or seed.

  7. Step 7 Fill the Well With Gravel

    Fill the Well With Gravel

    Leaving enough room at the top for a patio block cover, a topping of 2 to 3 inches of soil, and a layer of sod. Fold the ends of the landscape fabric over the gravel. Place a layer of gravel over the landscape fabric. Place a large concrete patio block on top of the gravel to keep water from entering through the top. Cover the patio block with 2 to 3 inches of soil and a layer of sod.

What You Need for This Project

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