How to Install Underground Drip Irrigation Pipe

How to Install Drip Irrigation Pipe. Installing underground irrigation pipe is the single biggest step when installing an automatic sprinkler system around your yard. The most common pipe used for this task is made of white PVC (polyvinyl chloride) and has an average usable life of 15 to 20 years before it needs to be replaced. The irrigation system will need to be well maintained in order for it to last that long, and repairs will need to be made along the way. But before any of that, the pipe must be connected, buried and used for its intended purpose.
Things Needed
Ground marking paint
PVC pipe
PVC pipe fittings
Trenching machine
Trenching shovels
PVC cutters
PVC primer
PVC glue
Hand tamper

Step 1

Plan the layout of your irrigation system. Study the layout of the landscape that will be irrigated and plan accordingly. There are many sprinkler supply companies that suggest ways to complete this, and plans are best accomplished according to the sprinkler manufacturer’s recommendations. There can never be too much irrigation system planning before you begin digging trenches.

Step 2

Mark the paths of the irrigation pipe with a can of ground marking paint. Call your utility companies to have them mark the utility lines that run through your yard. In many jurisdictions, you are required by law to do this.

Step 3

Dig trenches for the irrigation pipe that will be deep enough to avoid frost line issues in your area. Trenches can be dug by hand or with a trenching machine. Trenching machines are much faster and can be rented for a few hours or for a few days, depending on your needs and local availability. If you use a trenching machine, it is still wise to use trenching shovels to maintain the trenches during the installation process.

Step 4

Lay the pipe into the trenches. Cut the PVC pipe with PVC cutters and connect the pipe as you go according to your specific installation plan. PVC fittings are needed to create a fully customized installation. The different fittings you will need include tees, 90-degree elbows, 45-degree elbows, couplings, threaded nipples and sprinkler heads. Assemble these fittings and the pipe together using PVC primer and adhesive. Allow the glue to dry and cure before burying the pipe.

Step 5

Leave all fitting joints exposed after all of the fittings and pipe have been installed. Pressurize the system with irrigation water and check all of the fittings for water leaks. Replace the leaky joints as needed before burying the pipe.

Step 6

Bury the pipes after the fittings have been tested and no leaks have been found. The soil should be packed with a hand tamper. If you do not have access to a hand tamper, walk over the soil-filled trenches to pack the soil. Do not leave the trenches loosely filled. The soil will settle eventually and may settle unevenly. Packing the soil will speed the settling process.

Warnings
If you live in a climate that gets pretty cold, call your county extension office to find out how deep the frost line penetrates into the ground. If you bury the PVC pipe below this level, you will have little, if any, chance of having to replace frozen irrigation lines.