Home Garden

How to Install Subsurface Drains

A subsurface drain is a drain installed underground outside a house. It carries water away from the foundation before it can seep into cracks and damage your basement. All that is needed is a trench filled with gravel and a drain pipe. This style of drain, also called a French drain or a curtain drain, can be installed as a do-it-yourself project.

Things You'll Need

  • Stake
  • Shovel or excavator
  • Drainage pipe
  • Filter fabric
  • Shears
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Instructions

    • 1

      Locate a ditch or low, dry area on your property that is lower than your house. This will be the exit point for your subsurface drain, where all of the water is carried to. Mark this spot with a stake.

    • 2

      Call your local utilities to determine if there are any buried wires or pipes around your foundation and along the path between the house and the stake. Digging into buried wires and pipes is dangerous, and can result in expensive repairs.

    • 3

      Dig a 2-foot-wide ditch all around your foundation, or as close as you can get without disturbing buried wires and pipes, with a shovel. If you have a slab-on-grade house, the trench needs to be at least 2 feet deep. It should be 6 feet deep if your house has a basement.

    • 4

      Dig another ditch running from the first out to the stake. It should be as deep as the first one at its start, and slope further downhill from there.

    • 5

      Lay the drainage pipe into the ditch running away from the house. Use slotted drainage pipe instead of the kind with holes. It will be less likely to be clogged.

    • 6

      Fill both ditches with 1-inch gravel, up to 1 foot from the top. The gravel allows water around the house to quickly run to the bottom of the ditch and into the drainage pipe.

    • 7

      Cut strips of filter fabric that are as long and broad as the trenches. Lay these pieces on top of the gravel in the trenches.

    • 8

      Fill the rest of the space in the trenches with topsoil. Replant the grass that you removed when you dug the trenches.