How to Trench a Sprinkler System

Map out your sprinkler system on your lawn, according to manufacturer's instructions. Insert stakes into the yard to mark off where the sprinkler pipes will go. Place the first stake at the point in the lawn where the pipe will connect to the sprinkler system's control valves.

Tie twine to each stake and string them according to your design map. Tighten the twine to create a straight line between each stake.

Lay plastic tarps down on either side of the dig site of each trench. Preserve your sod and grass by gently inserting the shovel about 1 inch underneath the surface and prying it up out of the ground, taking the roots with it. Set each piece of sod onto the outer edge of the tarps so they won't be disturbed. Line them up in order so that you can put them back in their original place.

Determine the depth of your trench by adding 12 inches to the diameter of your sprinkler pipe. For example, a 2-inch diameter pipe needs a 14-inch deep trench. If you live where the ground freezes in the winter, dig to 18 inches or below the depth of the ground's frost line, whichever is deeper. Then add the diameter of the pipe to determine final depth.

Dig the trenches with a pick and shovel, using the twine lines between the stakes as your guide. Place the dirt onto the tarps so that you can refill the trenches once you lay in your sprinkler pipes.