In-Ground Sprinkler Troubleshooting

Once they've had an in-ground sprinkler system for watering lawns, there are few homeowners who would ever go back to using a manual lawn watering system. In-ground sprinkler systems can be counted as one of the greater conveniences of yard care. Maintenance problems do occasionally occur, however. Here's how to troubleshoot your in-ground sprinkler system.

1. Water Flowing from a Sprinkler Head

After the system has shut off, if water continues to flow from a sprinkler head, it's typically an indication of a valve problem. Here are a few suggestions:

  • If the water to the malfunctioning valve is turned on, shut it off.
  • Using a pipe wrench, unscrew and remove the top of the valve.
  • Check for particles of sand, dirt, etc., that could keep the valve from closing. Remove any particles found.
  • Check for cracks or holes in the valve diaphragm.
  • Check for particles on the valve seat and remove any that are found.
  • Reassemble valve components.
  • Check for normal valve operation by turning on the water flow to the valve. If the valve still fails to operate normally, your next action is to replace the valve.

2. Decrease In Water Pressure

If all sprinkling heads in a particular zone are functioning normally, but one fails to fully rise, it usually suggests there's a problem with water reaching the head. If you've unscrewed the head from the riser and find that there still is low water pressure, it could be caused by a broken pipe, a plugged riser or a leaky fitting.

Try these remedies:

  1. With the water shut off, replace the sprinkler head with a PVC cap screwed onto the riser. Turn the water on again and look for signs of water bubbling or springing from the ground in the area where your bad sprinkler head is located.
  2. Once you find this free-flowing water, mark the spot where it's coming out of the ground. Dig down to the pipe where you found the bubbling water. You should find a broken pipe or a leaky fitting. Replace the leaky fitting, or place a compression fitting on the broken pipe to fix the problem.

3. Total System Failure

If all your sprinklers fail to come on, there's a good possibility your sprinkler system control is at fault. As with all failing mechanisms that are powered by electricity, the first thing to check is the electrical power. If your control is getting power, you can try these other possibilities:

  • Do a manual "start" on one of the zones.
  • Check all the control's wiring connections.
  • Reset the control by disconnecting, then connecting to its power source.
  • Check to see that the control knob is in the right position.

If none of these remedies prove successful, chances are your controller should be replaced.