When one sprinkler zone stops working and the rest are fine, the fault is almost always in a short list of places: the controller program, the solenoid, a wire, or the valve itself. When every zone stops, the problem is upstream. Most of these checks take minutes and need nothing more than a screwdriver, and a good share of the dead-zone calls we get across Hamilton, Burlington and Oakville turn out not to be broken at all. Work through the steps below in order.
Quick diagnosis
If every zone is dead, check power to the controller, the rain sensor, and whether the water supply and backflow valves are fully open. If one zone is dead, open that zone's valve by hand: if it runs, the fault is electrical, meaning the solenoid, a wire or the controller station. If it will not run even by hand, the valve is clogged or damaged. If a zone will not shut off, there is debris in the valve. If a zone runs weakly with a soggy patch or a geyser, a pipe or head is broken, very often from freeze damage.
Diagnostic table: match your symptom to the cause
| Symptom | Likely cause | DIY check | Pro fix cost |
|---|---|---|---|
| All zones dead, controller screen blank | No power, tripped GFCI, failed controller | Reset the GFCI outlet, check the breaker | $150 to $300 basic controller |
| All zones dead, controller says running | Water off, backflow valves closed, rain sensor | Open supply and backflow valves fully, bypass sensor | $100 to $200 start-up visit |
| One zone never comes on | Failed solenoid or cut wire | Open the valve by hand | $85 to $160 solenoid, $150 to $450 wire repair |
| Zone runs by hand, not from controller | Solenoid, wire or controller station | Swap wires at the controller terminal | $85 to $450 |
| Zone will not run even by hand | Debris in valve, torn diaphragm, flow control shut | Open flow control, clean the valve | $120 to $250 rebuild, $180 to $350 replace |
| Zone will not shut off | Debris under diaphragm, blocked bleed port | Shut water, clean the diaphragm | $120 to $350 |
| Zone runs weak, soggy spot or geyser | Broken pipe or head | Walk the zone while it runs | $150 to $400 simple break, $600 to $2,500 freeze damage |
| A few heads do not pop up | Clogged head or low pressure from a leak | Flush the head, look for leaks | $35 to $75 per head installed |
Step 1. Check the controller
Start at the controller, because it is the cheapest problem to fix and the most often overlooked.
How to check
- Confirm the zone is included in the active program and has a run time greater than zero.
- Check the seasonal adjust or water budget setting. At 0 percent, nothing runs.
- Look for a rain delay, or a rain sensor that is still wet or has failed in the "wet" position. Most controllers have a sensor bypass switch: flip it and test.
- On a smart controller such as Rachio or Hydrawise, check the schedule history. Weather skips after rain are normal and look exactly like a fault.
- Run the zone manually from the controller and watch.
What it costs
Nothing if it is a setting. A replacement basic controller runs $150 to $300 installed, and a WaterSense smart controller $400 to $700.
Step 2. Check the water supply and backflow preventer
Most Ontario residential systems are fed from the house supply through a shutoff valve indoors and a backflow preventer outside, usually in a green box or near the foundation. If all zones stopped at once, especially just after a spring start-up, this is the first suspect.
How to check
Confirm the irrigation shutoff inside the house is fully open. At the backflow preventer, both ball valve handles should be in line with the pipe. A handle left at an angle after start-up restricts flow enough to stop rotors popping up. Make sure the small test cocks are closed.
What it costs
Nothing to reopen a valve. A leaking or split backflow assembly, usually from freeze damage, costs $250 to $600 to replace. In Burlington and Oakville the device also needs regular testing by a certified tester.
Step 3. Open the valve by hand
This one test splits electrical faults from mechanical ones, and it tells you which half of this guide you need.
How to check
Find the valve box for the zone, usually a rectangular green lid in the lawn or a bed. With the controller off, either loosen the small bleed screw on the valve a turn or two, or turn the solenoid (the black cylinder with two wires) a quarter turn counter-clockwise. Water should start flowing to that zone within a few seconds. Close it again afterwards.
- Zone runs by hand: the valve is fine. Go to Step 4, electrical.
- Zone does not run by hand: the valve is the problem. Go to Step 5.
Step 4. Test the solenoid and wiring
Residential valves run on low-voltage 24 VAC wiring, which is safe to handle. Leave the 120V side of a hard-wired controller to an electrician.
How to check
- Swap test at the controller. Move the dead zone's wire to a terminal you know works and run that station. If the dead zone now runs, the controller station has failed. If it still does not, the fault is in the field.
- Solenoid resistance. Disconnect the solenoid and measure across its two wires with a multimeter on ohms. Most residential solenoids read somewhere around 20 to 60 ohms. An open reading means a dead coil, and a reading near zero means it has shorted.
- Voltage at the valve. With the zone running from the controller, you should see roughly 24 to 28 VAC at the solenoid wires. Voltage at the controller but not at the valve means a broken wire.
- Splices. Open the valve box and look at the wire connections. A plain wire nut without waterproof grease corrodes, and it is one of the most common failures we find.
Where wires get cut
Core aeration, bed edging, fence post holes, new plantings and patio work. If a zone died shortly after any of those, start looking there. Before digging deeper than a hand trowel, request free locates through Ontario One Call.
What it costs
A replacement solenoid is $85 to $160 installed. Locating and splicing a broken wire with a wire tracer runs $150 to $450 depending on how long the run is and how hard the break is to find.
Step 5. Clean or rebuild the valve
A valve that will not open by hand, or one that will not close, is almost always debris or a worn diaphragm. Pipe repairs and spring start-ups both flush grit into valves.
How to check
Shut off the water supply to the system first. Check the flow control handle on top of the valve, if it has one: turned fully down, it shuts the zone off. Then unscrew the bonnet, lift out the spring and diaphragm, and look for grit, pebbles or a tear in the rubber. Clear the small bleed port with a pin. Reassemble with the diaphragm seated correctly and turn the water back on slowly.
What it costs
A diaphragm kit for a common valve such as a Hunter PGV or Rain Bird DV is inexpensive. A professional rebuild runs $120 to $250 and a full valve replacement $180 to $350, more if the manifold is buried without a box.
Step 6. Find the broken pipe or head
If the zone comes on but runs weakly, the water is escaping somewhere. In Ontario the most common cause by far is freeze damage from a missed or incomplete fall blowout.
How to check
Run the zone and walk it. Look for a geyser, a head that bubbles instead of spraying, water welling up in the lawn, or a patch that stays soggy. Heads that pop up but spray weakly may just be clogged: unscrew the nozzle, rinse the filter screen, and refit.
What it costs
A replacement head is $35 to $75 installed. A simple lateral break runs $150 to $400. Freeze damage across several points, or a split under a hard surface, runs $600 to $2,500.
2026 sprinkler repair costs at a glance
| Repair | Typical cost installed |
|---|---|
| Spring start-up visit | $100 - $200 |
| Fall blowout | $75 - $150 |
| Replace a sprinkler head | $35 - $75 each |
| Replace a solenoid | $85 - $160 |
| Rebuild a valve | $120 - $250 |
| Replace a valve | $180 - $350 |
| Locate and repair a broken wire | $150 - $450 |
| Repair a simple pipe break | $150 - $400 |
| Freeze damage, multiple breaks | $600 - $2,500 |
| Replace a backflow preventer | $250 - $600 |
| Basic controller, installed | $150 - $300 |
| Smart controller, installed | $400 - $700 |
If the system is more than about 20 years old and the breaks keep coming, it can be cheaper to rework the zones than to keep patching. Our irrigation system cost guide prices new systems and added zones.
When to call a pro
- The wire break is not in the valve box and you cannot trace it
- The valves are buried with no valve box
- Several zones failed at once and the controller and supply checks passed
- The backflow preventer is leaking, split or due for its test
- There is water coming up under a patio, driveway or walkway
How to prevent it next year
- Book a proper compressed-air blowout every fall. Our winterizing guide explains why partial blowouts cause spring breaks
- Replace plain wire nuts in valve boxes with waterproof grease-filled connectors
- Flag heads and wire runs before aeration, edging or planting
- Open backflow and supply valves slowly and fully at start-up
- Replace the controller backup battery each spring so programs survive a power cut
- Consider a smart controller that alerts you when a zone draws no flow
Frequently asked questions
Why is only one sprinkler zone not working?
When the other zones run normally, the fault is specific to that zone: most often a failed solenoid, a cut or corroded wire, or debris in the valve. Opening the valve by hand tells you whether it is electrical or mechanical.
How do I know if my sprinkler solenoid is bad?
If the zone runs when you turn the solenoid a quarter turn by hand but not from the controller, suspect the solenoid. Measure it with a multimeter: most residential solenoids read around 20 to 60 ohms, and an open reading means it is dead.
Why won't my sprinkler zone shut off?
Usually grit trapped under the valve diaphragm, a blocked bleed port, or a bleed screw left open. Shut off the water, open the valve, clean the diaphragm and bleed port, and check the solenoid is turned fully clockwise.
How much does it cost to fix a sprinkler zone in Ontario?
Most single-zone repairs cost $85 to $450 in 2026: $85 to $160 for a solenoid, $120 to $350 for valve work and $150 to $450 to find and repair a broken wire. Freeze damage with several breaks can run $600 to $2,500.
Can a bad controller make just one zone fail?
Yes, a single station output can fail. Move that zone's wire to a terminal that works. If the zone then runs, the controller station is the fault.
Why did my sprinklers stop working after spring start-up?
Most often a backflow valve or supply valve not fully opened, grit flushed into a valve, or freeze damage from the previous fall showing up as leaks. Check the valves first, then walk each zone while it runs.
Is it safe to work on sprinkler wiring myself?
The valve wiring is low voltage, around 24 VAC, and safe to handle. The 120V supply to a hard-wired controller is not a DIY job and should be left to a licensed electrician.
Can freezing damage stop a zone from working?
Yes. Water left in pipes, valves or the backflow preventer over winter expands and splits them. The zone may run weakly, leak, or not build enough pressure for heads to pop up.
If you have worked through the checks and the zone still will not cooperate, the Peace Love Landscaping crew repairs and services sprinkler systems across Hamilton, Burlington, Oakville and the surrounding area. Request a free assessment and we will find the fault and price the repair before any work starts. See also our irrigation and sprinkler service, the summer lawn watering schedule and the spring landscape start-up checklist.
Lawn yellowing where a zone failed? See how to tell stressed grass from dead in our yellow sod guide.