Stopping water flow to your irrigation system is necessary for sudden malfunctions or scheduled maintenance. Disabling the flow quickly prevents water waste, limits potential damage, and allows for safe repairs, whether you are addressing a burst pipe or replacing a sprinkler head. The process involves identifying several control points, ranging from the main system isolation valve to the individual zone mechanisms.
Locating the Main Water Shutoff Valve
The most effective way to turn off your sprinkler system completely is by isolating it at the main water supply line. This dedicated valve is typically located near the backflow prevention device or where the irrigation pipe branches off the main house line. It is often housed in a utility box outside, but may also be situated inside a basement or garage.
Two common valve styles are used for this main shutoff point: the ball valve and the gate valve. The ball valve is the most prevalent in modern systems and features a lever-style handle. To turn off the water, rotate this handle a quarter-turn (90 degrees) until it rests perpendicular to the pipe’s direction of flow.
The gate valve, less common in new installations, is identified by its multi-spoke wheel-style handle. Shutting off a gate valve requires turning the wheel clockwise for multiple full rotations until the handle stops rotating. Always apply steady, firm pressure when operating either valve type to avoid damaging the stem or handle.
Turning Off Individual Zone Valves Manually
For localized repairs or maintenance on a single section, you can manually shut off the specific zone valve without disabling the entire system. These valves are grouped together in a manifold, usually contained within a plastic valve box accessible in the ground. The electric solenoid sits atop each valve and controls the water flow based on signals from the controller.
To manually close a zone valve, two common methods exist, depending on the valve design.
Using the Bleed Screw
The first method uses the manual bleed screw, sometimes called a weep screw, located on the valve body opposite the solenoid. Slowly turn this screw clockwise until it is hand-tight to force the valve diaphragm to seal and stop the flow.
Using the Solenoid
Alternatively, many valves allow for manual operation directly via the solenoid itself. By firmly grasping the solenoid and twisting it clockwise a quarter-turn, you can manually override the electric signal and force the valve to close. This technique is often preferred because it avoids water escaping and filling the valve box, which can happen when using the bleed screw.
Shutting Down the System Controller
Before any physical work begins on the plumbing, disable the system’s controller or timer. This step prevents the system from unexpectedly cycling on and re-pressurizing the lines while you are working. The simplest way to achieve this is to turn the controller’s main dial or setting to the “Off” or “Rain” position, which suspends all automatic watering schedules without erasing the stored programming.
For complete electrical isolation (advisable for extended maintenance or winterization), physically unplug the controller if it is a plug-in model. If the unit is hardwired, locate the dedicated circuit breaker and switch it off at the main electrical service panel. Turning off the controller is only an electrical shutoff and does not physically stop water flow if a valve is stuck open or leaking.
Troubleshooting a Stubborn or Leaking Valve
If a valve refuses to close completely or continues to leak after attempting a shutoff, immediate practical steps are required. If the main sprinkler shutoff valve is stiff or inaccessible, the ultimate emergency measure is to turn off the main water valve for the entire house. For a slightly stiff main valve, applying gentle, steady force or a small amount of penetrating lubricant can sometimes free up the mechanism without causing damage.
If a zone valve is the source of a persistent leak, the issue is often mechanical, typically caused by debris preventing the internal diaphragm from sealing. Attempt to flush the valve by manually opening it slightly using the bleed screw for a few seconds, then closing it again to dislodge any grit or sediment. If the valve continues to weep, the internal components may be damaged. If the leak cannot be contained or requires disassembly beyond external adjustments, contact a professional irrigation technician.