Before the first freeze, shut off the water, set the controller to off, and get the water out of the pipes. Hunter, Rain Bird and Rachio all suggest a pro for the air blowout.
Only needed where pipes can freeze. Hunter says winterizing is done before the first freeze in regions where frost goes deeper than the buried pipes (Hunter). Rain Bird’s tips are for regions where it freezes (Rain Bird).
Check this first
Turn off the water to the sprinklers. Wrap the main shutoff valve with foam insulation tape and a plastic bag. Insulate any above-ground pipe (Rain Bird).
Set the controller to OFF or rain mode, and leave the power on. Your settings are kept and the valves won’t run (Hunter, Rain Bird). On a Rachio, turn on Hibernation Mode in the app (Rachio).
Get the water out of the pipes. Systems drain by manual drain valves, automatic drain valves or a compressed-air blowout (Rain Bird). Only use manual drains if you know they sit at the ends and low points of the pipe (Hunter).
Protect the backflow preventer and above-ground valves. Wrap them with insulation tape, but don’t block the air vents or drain outlets (Rain Bird). Flow sensor? It should come out before a blowout (Hunter).
Rain sensor with a cup? Empty it and cover it with a plastic bag (Hunter).
Hose timer? If nights will drop below 35°F, take it off the faucet, drain it and store it indoors. Take the batteries out first (Rachio).
Compressed air can cause serious injury, including eye injury. Hunter says it is best for a qualified licensed contractor to do the blowout (Hunter). Rain Bird recommends contacting your local irrigation specialist (Rain Bird), and Rachio also suggests a professional (Rachio).
Safety points from Hunter’s winterizing guide (Hunter):
Wear ANSI-approved safety eye protection and don’t stand over pipes, sprinklers or valves while there’s air in the system (Hunter).
Keep pressure low: no more than 50 psi for flexible black (polyethylene) pipe or 80 psi for white PVC (Hunter).
Shut off the water first, connect after the backflow device, and never blow air through the backflow (Hunter).
One zone at a time, starting farthest from the compressor, until no water comes out (about 2 minutes or more). Stop once it’s dry (Hunter).
Always keep a valve open while the compressor runs, and never leave the compressor unattended (Hunter).
Adapter to connect a compressor
Vibrant Yard Co. sprinkler winterize adapter with valve (20 in.)
Connects an air compressor to a garden-hose faucet: 1/4 in. quick-connect plug, 3/4 in. hose threads, brass shut-off valve and 20 in. hose rated 250 psi. Includes a male-to-male fitting and winterization instructions.
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Why it matters: water left in pipes can freeze, expand and crack PVC pipe, and freezing water can crack a brass backflow body (Hunter). Book early: pros often fill up weeks ahead (Rachio).
When to call a pro
Air blowouts are risky without the right compressor and safety gear. The EPA suggests hiring an irrigation professional certified by a WaterSense labeled program (EPA WaterSense).
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Steps summarized from the linked manufacturer and EPA pages (checked 2026-10-18). If your valve or head brand differs, follow its manual.
▶ Watch howWinterizing a Hunter Irrigation ControllerOfficial Hunter Landscape Irrigation video on YouTube ↗