How to Install Drainage Around a Patio to Avoid Standing Water

Prevent water build-up in your yard by building an underground drain. We'll walk you through the simple 4-step process.

yard with two chairs
Project Overview
  • Total Time: 3 hours
  • Skill Level: Beginner

Many yards naturally have areas that collect water, a problem that creating a new patio or path can actually make worse. Water can't soak through the hard surfaces of a patio or path, so it runs into the yard. This runoff can cause problems you should correct before you start construction. Fortunately, there are easy-to-install solutions for carrying the water away.

A swale or French drain channels the water away from the site to an area where it won't cause problems. You can divert water to another spot on your own property, but, not to the neighbor's yard, so if you can't divert the water to a good location, you'll have to run a French drain to a dry well.

A dry well collects water and allows it to seep slowly into the surrounding soil. Look to your local codes for the required dry-well size for your area. The size can be subject to your property's conditions, or to the neighborhood's. Even if your yard has no runoff problems, you can avoid creating them by installing a gravel-lined trench around the patio.

First, check for the location of underground utility lines before you start installing any kind of drainage system.

What You'll Need

Equipment / Tools

  • 1 Round-nose shovel
  • 1 Slope gauge
  • 1 Spade
  • 1 Scissors

Materials

  • 1 Gravel
  • 1 4-inch perforated drainpipe
  • 1 Couplings
  • 1 Landscape fabric
  • 1 Concrete patio block

Instructions

  1. Dig and Line the Trench

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    Using a spade, slice the sod along the path of the line, about two feet wide. Remove the sod, roll it up, and save it. Dig out the trench about 6 inches deep all along the line, using a slope gauge to slope it 1/4-inch per foot. At the low end of the trench, dig a dry well about two to four feet wide and three feet deep. Line the trench with landscape fabric and gravel. Then lay in 4-inch perforated drainpipe with the holes facing down. Continue running pipe a few inches into the dry well. Connect the pipe sections with fittings, not with glue.

  2. Fill with Gravel

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    To keep the gravel from settling into the soil, line the well with landscape fabric, leaving about two feet of surplus fabric on each side. Cut a hole for the drainpipe, then fill the trench and the well with gravel, leaving enough clearance over the well for a 2- to 3-inch-thick patio block cover.

  3. Cover the Well

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    Fold the well's surplus landscape fabric over the gravel and cover it with a patio block. Backfill the trench and the well, tamping the soil lightly.

  4. Replace the Sod

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    Cover the patio block with at least three inches of soil, tamping it lightly with a garden rake, then roll the sod back over it.

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