Winterizing Your System

I've repaired more freeze damage than I care to count. Cracked pipes, split valve bodies, shattered backflow preventers — all completely preventable with proper winterization. This is the one maintenance task you absolutely cannot skip.

When to Winterize

Winterize before your first hard freeze (sustained temperatures below 32°F). In most areas, this is late October to mid-November. Don't wait until it's already freezing — by then it might be too late.

The Blow-Out Method

This is the professional method, and it's what I recommend for everyone.

What You'll Need

• An air compressor capable of at least 50 CFM at 80 PSI (you can rent one)
• A blow-out adapter that fits your system's main line
• Safety glasses (seriously — debris can fly out of heads)

Steps

1. Turn off the water supply to the irrigation system.
2. Turn off the controller or set it to "rain" mode.
3. Connect the compressor to the blow-out port (usually at the backflow preventer or main line).
4. Start with the zone farthest from the compressor. Open that zone on the controller or use the manual bleed.
5. Blow air through at 50-80 PSI (never exceed 80 PSI for PVC, 50 PSI for poly pipe). Run until the heads are just spitting mist — about 2-3 minutes per zone.
6. Move to the next zone and repeat. Work from farthest to nearest.
7. Run each zone twice to make sure all water is out.
8. Don't forget the main line between the shut-off and the first valve.

Important Warnings

• Never run the compressor with all zones closed. The pressure can damage pipes and valves.
• Never stand over a head during blow-out. Rocks and debris shoot up fast.
• Don't over-blow. Running the compressor too long on a dry system generates heat that can melt PVC fittings.

Don't Have a Compressor?

You can also drain the system manually if you have drain valves at the low points. Open them, open all manual drain valves on the valves, and let gravity do the work. This won't get all the water out, but in mild freeze areas it may be enough.