How to Troubleshoot the Water Pressure in Sprinkler Lines

Sprinkler systems rely on steady water pressure to force up sprinkler nozzles and ensure even water coverage. If your sprinkler system develops a crack in the underground supply line, the pressure will fall and you will have to make a repair. Although sprinkler supply lines are buried, it's possible to narrow down where the leak is happening by testing the water pressure at each sprinkler head along the line. The point where the pressure dips is likely near the leak, giving you a great starting point for finding the crack.

Hand shovel
Water pressure gauge with 1/2-inch inlet
Hose repair clamp
Screwdriver

Instructions

- 1
  Remove the dirt around each sprinkler head on the zone where you suspect there is a problem. Clear an area about 6 inches deep and 6 inches around the base of each sprinkler head.
- 2
  Remove the first sprinkler on the line by twisting it counterclockwise until it pulls free. The first sprinkler is the one closest to the manifold.
- 3
  Screw in the water pressure gauge and turn on the sprinkler system by setting the controller to "Run" or "Start."
- 4
  Record the pressure reading on the first sprinkler. This is the base number that you use to compare all the other heads to.
- 5
  Remove the pressure gauge and reinstall the sprinkler head.
- 6
  Continue moving down the line of sprinklers, removing each one, inserting the pressure gauge, turning on the system and recording the pressure reading.
- 7
  Compare the pressure readings from each head. They should all be nearly the same until you've reached one nearest the crack in the line. Where the pressure begins to have a noticeable dip of 20 or more PSI is likely the place near the crack underground.
- 8
  Dig up about 8 inches of dirt around the base of the sprinkler where the dip was noted, moving the trench back in a straight line toward the prior sprinkler head.
- 9
  Turn on the sprinklers and look in the trench for water that sprays erratically from the supply line. This is where the system is losing water pressure from.
- 10
  Turn off the sprinklers.
- 11
  Clamp a hose repair bracket around the area of the crack, tightening the two screws on the edges of the bracket. The rubber gasket on the inside of the repair bracket presses against the crack, sealing it and making it watertight.
- 12
  Replace the dirt in the trench and around the sprinklers and turn on the system. You should notice an improvement in water pressure right away.

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