What it usually means, the likely causes in order, what to safely try first, what a pro charges in Canada, and when to stop and call one.
This guide covers the common cases. Describe your exact problem and get a personalized diagnosis — free to start, with a DIY vs. call-a-pro verdict and a real cost estimate.
A controller or timer that is not running, or not scheduling correctly, leaves the lawn at the mercy of a clock nobody is watching: zones may never run, run at odd hours, or run far too often. The common causes are unglamorous — a power issue, a dead backup battery that wipes the program after every outage, or a programming error rather than a broken machine. That makes the first checks clerical, not technical: is it powered, does it know the correct time and day, and does a manual test cycle run the zones? Separating a controller fault from a zone fault is the key move, and the manual test does it in minutes.
A controller fault is not an emergency, but during hot or dry weather every missed cycle counts, and an overwatering fault wastes water and can soften soil around paths and foundations. Attend to it within days in summer. If the controller is running zones far too long, or rain is forecast while it insists on watering, switch it off or to a rain delay rather than letting a confused timer make expensive decisions on your behalf.
A tripped outlet, an unplugged transformer, or a failed backup battery can leave the controller blank, reset, or amnesiac after each small outage. The classic story is a program that keeps disappearing: the battery that should preserve it through outages is exactly the part owners forget exists.
Wrong start times, multiple start times stacked by accident, zones set to zero minutes, seasonal adjustment left at an extreme, or the wrong day schedule can all produce a system that runs oddly while being mechanically perfect. This is especially common after well-meaning button pressing by several household members.
A rain sensor stuck in the off position, a freeze sensor, or a smart controller following weather data for the wrong location can suppress watering that looks scheduled. The controller is obeying an input the owner has forgotten about, which feels identical to a fault from the lawn point of view.
A corroded common wire, a loose terminal, or damaged field wiring can stop some or all zones responding even though the controller display and program look correct. Zones that fail together in groups, or a controller that commands a zone the manual test cannot wake, point this way.
| Job size | Typical estimate (CAD) |
|---|---|
| Simple fix — the straightforward version of this repair | $90–$150 |
| Major job — complex, hidden, or replacement-level work | $150–$500 |
Estimates only, calibrated to Greater Toronto Area trade rates and adjusted by region on this site — not a quote. Your exact price depends on the cause, parts, and access. A personalized diagnosis narrows this range using your specific symptom.
Replacing a backup battery, correcting time and program, clearing a forgotten rain delay, and reconnecting a smart controller to its app are all reasonable homeowner fixes. Call a pro when manual tests show zones not responding and wiring checks look sound, when several zones fail in a group suggesting a field wiring fault, when the controller itself is dead despite confirmed power, or when you want an older timer replaced and the valves re-mapped properly at the same time. Bring your program notes to the visit.
The usual reason is a dead or missing backup battery. The main power keeps the display alive day to day, but during even a brief outage the battery is what holds the clock and schedule. Without it, the unit wakes up reset and either does nothing or follows defaults. Replacing the battery and then re-entering the program once is the fix; replacing the controller is rarely needed for this symptom alone.
A successful manual run proves the valves, wiring, and water supply all work. The fault is therefore in the scheduling layer: wrong time or day on the clock, start times not set as you think, an active rain delay or sensor holding the system off, or seasonal settings reducing runs to nothing. Work through the program screen by screen rather than suspecting the hardware that just demonstrated it works.
Either there is no rain sensor, the sensor has failed or dried out slowly and needs attention, or a smart controller is using weather data that does not match your property conditions. It is also possible someone set a manual cycle. Check sensor status in the controller menu first, and use rain delay as your immediate control while the underlying cause is sorted out.
It can be worthwhile when the old unit is failing, hard to program, or wasting water through crude scheduling, since app control and weather-based adjustment make correct watering easier to maintain. It is not a fix for bad valves or wiring, though: a new controller on a faulty field wire disappoints quickly. Have the zones proven working, manually, before or during the upgrade conversation.
Describe what's actually happening and get a personalized diagnosis — DIY vs. call-a-pro verdict, real cost estimate, and top-rated local pros.