Things You'll Need
Utility knife or pipe cutter
Swing joint riser
Plants grow and change the landscape over the course of a season. When they grow too much, plants can interfere with the arc of water from a sprinkler system. That means the spray is hitting the back of a trunk or bush and can't get to the front of the bed. Sometimes this is also the result of incomplete planning. When an irrigation system is installed in fall or prior to planting a bed or zone, it is common to find problems with spray in spring after plants have been placed. However, it is very simple to replace an existing sprinkler head with a riser that will allow the water to spray out higher and avoid any obstacles.
Use a screwdriver to unscrew the little screw at the top of the sprinkler head. Pull off the head and turn it upside down. Place the screw inside the underside of the sprinkler so you don't lose the tiny connector.
Check the sprinkler head for cracks or damage. Now is a good time to replace any broken heads. Also check the T-pipe under the head for any damage or leaking and replace it if necessary.
Wrap the riser threads with Teflon tape to help ensure a tight fitting. Make sure you choose the right height of riser or you can install a poly cut-off riser. This type of riser can be cut off to the appropriate level with a pipe cutter or sharp utility knife.
Screw the riser into the T-pipe until it stops moving. The fitting should be tight enough without the use of any putty or glue. Glue should not be used in any case as it might drip down into the piping and cause a blockage. Screw the sprinkler head back on and turn on the system to test.
Swing Joint Riser
Dig along the sprinkler where you are going to install the swing joint riser. These types of risers allow you to move the position of the sprinkler head without digging up the pipe every time.
Unearth the pipe just a few inches away from the existing sprinkler head. Detach the old straight, stiff pipe that attached to the main PVC water line. Insert an ell or connection which came with the swing joint riser. Wrap Teflon tape around the end of the ell. It screws into the main water line and is self-locking.
Add another ell to the end of the riser pipe and run it up toward the bottom of the sprinkler head. Insert it into the bottom of the T-pipe. Use Teflon tape again and screw it in tightly. Turn the system on to check that the swing joint riser is allowing the sprinkler head to rotate.
Fill in the trench you made to get at the pipe. It is a good idea to install swing joint risers on every sprinkler head so you don't have to dig up the irrigation system to make changes to the sprinkler heads.