Proper Depth for In-ground Sprinkler Heads

Sprinkler Size

• How long your sprinkler is will largely dictate how deep to install it. Most sprinklers come in standard sizes of 2, 4, 6 or 8 inches. That measurement is located on the label of the sprinkler, but you can use a ruler or tape measure to double check the length. The length of a sprinkler should be measured from the top of the nozzle to the base of the riser hole on the bottom of the sprinkler. You must trench at least this length for proper installation.

Riser Depth

• If you end up trenching your lines much deeper than the size of your sprinkler heads, you can make up the difference in the sprinkler riser. Risers are plastic pieces that attach the sprinkler to the supply line below. Trenches that are deeper than the size of your sprinkler head will require the use of a longer riser. Risers come in a wide variety of sizes, but cutoff risers are ideal for making custom sizes. The size of the riser you need is based on the depth of the trench minus the length of the sprinkler head.

Supply Line

• The supply line below will also impact the depth of your trench line. Measure the diameter of your pipe with a flexible tape measure, or see if the size of the pipe is printed on the pipe itself. Most sprinkler lines are 1-inch pipes, which means that you need to account for at least 1 inch of depth when digging your trench in addition to the length of the sprinkler head and the sprinkler riser.

Above-ground Sprinklers

• Some sprinkler heads will be installed permanently above ground. These are useful for watering crops or large gardens where running a lawn mower is not a concern. Trenching for these lines is much more shallow. The trench only needs to be deep enough to account for the supply line and the sprinkler riser. Usually, that means trenching only about 3 inches as the sprinkler will sit above the surface level.