Sprinklers Run Uncontrollably When Main Water Turned On

When the main outdoor water is turned on, sprinklers activate immediately and won't shut off until the main is closed. The user wants an easy fix.

Troubleshooting Steps

1. Unplug the controller to rule out a controller malfunction sending constant power.
2. Wait a few minutes—valves drained for a long time may need time to reseat and close.
3. Check manual bleed screws on valves to ensure they weren't left partially open.

If these don't resolve it, Matt asks for the system manufacturer and model number to provide more specific guidance. The issue is likely a valve stuck open (debris, worn diaphragm) or a controller failure, but the manual bleed check is the fastest first step.