Power Outage Causes Sprinkler to Run Uncontrollably: $700 Water Bill

Can a Power Surge Make an Irrigation Valve Stick Open?

A homeowner returned from a 17‑day vacation to find their Irritrol Rain Dial‑1200 controller running a zone nonstop. A neighbor reported a power outage during the absence. The water bill jumped from $190 to $700. The user manually shut off the water at the isolation valve, reset the controller, and the system now operates normally.

Two Possible Scenarios

1. Controller malfunction: A power surge may have corrupted the controller's programming, causing it to continuously energize a zone.
2. Valve mechanical failure: The valve's diaphragm, solenoid plunger, or debris could keep the valve open independently of the controller.

Follow‑Up Clarification

The gardener found the system running, shut off the isolation valve to work, then reopened it. The controller would still be able to complete its watering cycle because the controller itself was not powered down—only the water supply was interrupted. Without knowing the exact programming state after the surge, it's impossible to determine whether the controller or the valve was the root cause.

Practical Advice

• Contact the water utility; many offer one‑time forgiveness for documented equipment failures.
• Reset the controller (unplug, remove battery, wait 5 min, hold reset 5‑10 sec).
• Reprogram all schedules and install a fresh backup battery.