Home › Winterize sprinklers

How to Winterize a Sprinkler System: Drain Methods and When to Call a Pro

Updated October 31, 2026 · General information, not plumbing or legal advice

Some links on this page are affiliate links. If you buy through them we may earn a commission at no extra cost to you. How we make money.

The short answer: Shut off the water supply, then drain the system. Colorado State Extension says compressed air is the only positive way to be sure enough water is out, and University of Minnesota Extension says a certified irrigation professional should do the blowout. Never blow air through a backflow preventer, and never use antifreeze in the lines.

Safety first. Never thaw a pipe with a torch or any open flame. They are a fire hazard and can release deadly carbon monoxide. Keep electrical cords away from water, and stay out of rooms where water is near outlets, panels or appliances.

Why it matters

Texas A&M AgriLife Extension lists sprinkler lines among the pipes most vulnerable to freezing, and says to drain them following the installer's or manufacturer's directions. University of Minnesota Extension says water left in a sprinkler system can freeze and burst pipes.

Your drain options

Method	What the extension pages say
Manual or automatic drain valves	Colorado State Extension does not recommend relying on gravity drains, since sub-surface pipes tend to shift with time and you can't inspect the lines afterward.
Compressed-air blowout	Colorado State Extension: "The only positive way to be sure enough water has been expelled from the system is by using compressed air." Systems with electric valves need this method. University of Minnesota Extension says it should be done by a certified irrigation professional.
Pump	Colorado State Extension says to remove a pump and store it indoors. If you can't, drain it and insulate it.

Sources: Colorado State University Extension, University of Minnesota Extension.

The basic order (University of Minnesota Extension)

Inspect. Run each zone and look for leaking or broken heads. Repair them.
Shut off the water supply between the water source and the backflow preventer. It may be indoors or in a valve box outside.
Relieve pressure by manually opening the irrigation valves.
Open the drain valves in the valve box to release leftover water.
Blow out the lines with compressed air (a professional's job, per University of Minnesota Extension).
Set the controller to OFF. Colorado State Extension adds that you can keep it powered and run a short cycle weekly to help prevent solenoid plungers from sticking.

If you do a blowout (Colorado State Extension)

Stay within 80 psi for rigid PVC and 50 psi for polyethylene pipe.
Run one zone at a time. Too much airflow heats the pipe and fittings and can melt them, and too little lets air ride over the water and leave it in low spots.
Do not re-blow a zone that is already clear.
Never blow compressed air through a pressure vacuum breaker (PVB) or reduced pressure (RP) backflow preventer. Drain them following the page's steps and leave the ball valves at about 45 degrees for winter.
Wear eye protection and keep pets away, because the whistling can scare them.

When to call a pro

University of Minnesota Extension says: "The best, and safest, way to winterize your system is to leave it in the hands of a certified irrigation professional." It notes some landscape contracts already include winterizing, and suggests a WaterSense or Irrigation Association certified professional. Call one if you don't know your system type, can't match a compressor to your zones, or have a backflow device you aren't sure how to drain. We didn't find a sourced price, so we don't quote one. Ask for the price before booking.

Not sure about the blowout?

University of Minnesota Extension says the safest way to winterize is to leave it to a certified irrigation professional.

Sprinkler winterizing guide Get a quote from a sprinkler pro

Don't forget the outdoor faucets

Texas A&M AgriLife Extension and FEMA both say to cover outdoor faucets. Missouri Extension suggests an insulating foam dome.

How to use faucet covers See outdoor faucet covers

Related guides

Common questions

What are the ways to winterize a sprinkler system?

Colorado State Extension describes manual or automatic drain valves (which it does not recommend, since underground pipes tend to shift over time) and a compressed-air blowout, which it calls the only positive way to be sure enough water has been expelled.

Can I blow out my sprinklers myself?

University of Minnesota Extension says the blowout should be done by a certified irrigation professional, and notes consumer compressors lack the airflow of commercial ones. Colorado State Extension gives a DIY procedure with strict limits. If you are not sure, hire a pro.

What pressure is safe for a blowout?

Colorado State Extension says the maximum is 80 psi for rigid PVC pipe and 50 psi for flexible black polyethylene pipe. Too much airflow can heat and melt pipe and fittings.

Should I put antifreeze in the sprinkler lines?

No. Texas A&M AgriLife Extension says not to, because antifreeze is environmentally harmful and dangerous to humans, pets, wildlife and landscaping.

Sources