How to Dig Under a Sidewalk for Irrigation

By Kimberly Johnson

When planning or installing an irrigation system for your yard, you must connect a complex system of pipes to a single water source. In many cases, this requires running pipes under a sidewalk. Digging a trench underneath the sidewalk is not as challenging as it may seem at first. Using water makes the process go faster. However, the process is messy, so put on old clothes before starting.

List of Items Needed

  • Tape measure
  • Marker
  • 2- to 3-inch-diameter PVC pipe
  • Spade
  • Hacksaw
  • Handheld rotary tool
  • Cut-off wheel
  • Pressure washer
  • 0 degree nozzle
  • Garden hose
  • Safety glasses
  1. Place a tape measure on one side of the sidewalk and stretch it to the other side to measure the width. Transfer the measurement to a 2- to 3-inch-diameter PVC pipe using a marker. Cut the pipe off at the marked location using a hacksaw or a rotary tool equipped with a cut-off wheel.

  2. On one side of the sidewalk, use a spade to dig a 2-foot-deep and 6-inch-wide trench perpendicular to it. The trench should be approximately 12 inches longer than the PVC pipe. Dig another trench on the opposite side of the sidewalk that is large enough to grasp the pipe once it comes out.

  3. Attach a 0-degree tip to the end of a pressure washer and screw a garden hose onto the inlet valve on the machine.

  4. Put on safety glasses and place the PVC pipe into the trench butting the end up against the soil directly under the sidewalk. Insert the wand of the pressure washer into the opposite end of the PVC pipe and push it forward as far as possible.

  5. Turn the pressure washer on and push the PVC pipe repeatedly against the soil as the water drills through it. Continue the process until the pipe comes out on the opposite side of the sidewalk.

Tips and Warnings

  • You can either remove the PVC pipe when you are done, or leave it in place and insert any new pipes through it.

© Demand Media 2011