Calgary Irrigation Fall Shutdown Checklist: 12 Steps Before the Freeze

A properly executed fall shutdown is the most important maintenance event in your Calgary irrigation calendar. Done right, it protects $4,000–$10,000 of underground pipe and equipment from a single hard freeze. Done wrong, spring startup becomes a repair bill. This checklist walks you through every step — in the right order.

Calgary Irrigation Fall Shutdown: The Complete 12-Step Checklist

Step 1: Stop All Active Watering Schedules

Set your irrigation controller to Rain Hold or completely disable all active programs. Do this at least 48–72 hours before your scheduled blowout to allow the soil to drain residual moisture from around the heads.

Step 2: Stop Adding Fertilizer to the Lawn

Cease any fertilizer or chemical applications connected to the irrigation system at least 2 weeks before shutdown. Fertilizer residue in lateral lines increases the risk of mineral buildup and corrosion during winter dormancy.

Step 3: Schedule Your Professional Blowout

Book your professional irrigation winterization appointment. For most Calgary areas, this should be completed between October 1 and October 15. Northwest Calgary and Airdrie/Cochrane should aim for late September to early October. Once overnight temperatures drop consistently below +2°C, prime booking windows close rapidly.

Step 4: Locate and Test the Main Shutoff Valve

Locate your irrigation main shutoff — typically in the basement, utility room, or meter pit. Turn it to verify it operates freely. A seized main shutoff valve discovered on blowout day delays the entire procedure and requires immediate repair.

Step 5: Identify Your Backflow Preventer Location

The backflow preventer must be drained as part of winterization. Locate it and ensure it is accessible to the technician. If it is installed above grade and exposed (common on older Calgary systems), ensure the outdoor access is clear of obstructions.

Step 6: The Professional Compressed Air Blowout

Your licensed technician connects a trailer-mounted rotary screw compressor at 50–100 CFM to the system and activates each zone individually at the controller. Each zone is blown 2–3 times until no water mist appears at the sprinkler heads. Heads pop up, blow clear, and retract. This step must NEVER be DIY-attempted with a standard shop compressor — insufficient CFM leaves water in deep lateral lines where it freezes and cracks pipes.

Step 7: Drain the Backflow Preventer

The technician opens the drain cocks on the backflow preventer body (typically two small quarter-turn petcocks) to drain residual water from the device housing. On RPZ devices, the relief valve chamber is also drained. Failure to drain the backflow preventer is one of the most common causes of expensive device failure during Calgary winters.

Step 8: Drain Valve Manifold Boxes

Open valve box lids to confirm water is draining from around valve bodies. Check that drainage holes in the bottom of each valve box are clear — clay soil silt frequently blocks these holes over time, allowing water to pool and freeze around solenoid bodies.

Step 9: Disconnect and Drain Hose Bibs

If you have exterior hose bibs connected to the irrigation system, disconnect garden hoses and drain residual water from the bib. If you have a standard (non-frost-free) exterior tap shared with irrigation, shut the indoor valve and open the exterior tap to drain.

Step 10: Set the Controller to Standby

After the blowout, set your controller to OFF or to its designated rain/standby mode. Do not unplug or remove power completely from smart controllers — power loss during winter can reset programming and satellite data on some models. Keep the controller plugged in but set to OFF.

Step 11: Insulate Above-Grade Components

Any components that remain above ground — above-grade backflow devices, hose bib extensions, or visible supply pipes — should be wrapped with pipe insulation and covered with an insulating cover. Even drained components can accumulate frost that damages gaskets and O-rings over repeated freeze-thaw cycles.

Step 12: Document and Schedule Spring Startup

Note the shutdown date, technician contact, and any issues flagged during winterization. Book your spring startup immediately — April is the most common date for Calgary, and technicians fill quickly. A pre-booked spring startup means your system is first in line when the ground thaws.

Book Your Calgary Irrigation Winterization Now

J&G Irrigation performs professional irrigation winterization across Calgary, Airdrie, Cochrane, and Okotoks. Our technicians use trailer-mounted rotary screw compressors and service every zone until completely clear. October slots are filling — call (403) 992-6743 or book online now.