If your irrigation system is leaking, do the following:
Step 1: Turn off the controller
Make sure the irrigation system’s controller is OFF. On most controllers, you do this by turning the large knob on the face of the controller from “AUTO” or “RUN” or “OFF”.
More advanced smart controllers will have a touch screen or other arrangement. You may be able to disable the controller by scrolling through prompts on the screen. If not, unplug the controller.
Step 2: Turn off water to the supply to the irrigation system
However, if a valve is failing to close, shutting off the controller will not stop the leak. In this case, you will need to cut the water supply to the irrigation system.
Newer systems should have a manual cutoff valve in a ground box on the irrigation mainline connected to the property’s service line. This round valve box will be right before the square box containing the backflow prevention assembly.
If you cannot locate the cutoff, use the handles on the backflow assembly to close the backflow preventer. Closing just one should do the trick. Often the backflow preventer and manual cutoff will be very close to the water meter.
Note: Using the manual cutoff or the backflow preventer cutoff handles will cut water to the irrigation system without shutting water to the house.