How to Tunnel Under a Sidewalk for Sprinkler Pipe

Running irrigation under a sidewalk can be done with simple tools.

When installing a sprinkler system, you may need to cross under a sidewalk to connect landscape or lawn areas to your irrigation zones. There are many specialized devices that can accomplish the tunneling, but the task can also be accomplished using materials you probably already have.

Things You'll Need

• Shovel
• Irrigation pipe
• Hacksaw or PVC pipe cutter
• Hammer or mallet
• Scrap piece of lumber

Instructions

1. Dig a trench on each side of the walk at the location where the pipe needs to cross, running in the direction the pipe will take. The trench should be deep enough to go under the walk and extend for about two feet on either side.

2. Cut the irrigation pipe at least two feet longer than the walk is wide. One end should be cut to a point at a 45° angle.

3. Place the pointed end of the pipe in the trench and press it into the soil under the walk.

4. Pound the other end of the pipe with a hammer or mallet, using a piece of scrap lumber over the end of the pipe to protect it from cracking or splitting while being pounded. Guide the angle of the pipe so that it runs horizontally under the walk. Continue pounding until you drive the pipe completely under the walk and it emerges in the trench on the other side.

5. Connect one end of the pipe to the irrigation system or a hose and flush it with water before connecting the remaining elements of the sprinkler system.

Tips & Warnings

• For rocky or heavily compacted soils, you may need to use a metal pipe or rod to drive an opening under the walk before pushing the irrigation pipe through.

• A pressure sprayer or garden hose with a jet nozzle, inserted inside the pipe, will help loosen the ground under the walk as you push the pipe through.

References

• Ask the Builder: Tunneling Under Sidewalks and Driveways