How to Properly Winterize Your Sprinkler System in Colorado

In Colorado, winterizing your sprinkler system is a must. With freezing temperatures throughout the winter, failing to prepare your system can lead to costly repairs in the spring. Proper winterization ensures your pipes, backflow preventer, and sprinkler heads stay safe from freeze damage.

The best option is to call a professional, as they have the tools and experience to do the job efficiently. However, if schedules are tight or you’re unable to book someone, here’s a step-by-step guide to help you winterize your system yourself.

Step 1: Rent an Air Compressor
You'll need an air compressor with at least 10 CFM (cubic feet per minute) capacity to efficiently blow out the water from your system. A lower-rated compressor may work, but it will take much longer and may not be as effective.

Step 2: Prepare the System and Connect the Compressor

• Shut off the water to your sprinkler system at the main valve inside your home.
• Open any drain valves to release water in the pipes, allowing it to flow out.
• Close the ball valve on the backflow preventer that connects to your house to ensure air is directed only into the sprinkler system.
• Ensure you have the proper fittings to connect the air compressor to the petcock on the backflow preventer.

Step 3: Blow Out the Zones

• Attach the air compressor line to the petcock and slowly build the pressure in your compressor to 90 PSI (keep it under 100 PSI as most irrigation systems are rated for 100-120 PSI).
• Make sure the flathead screw on the petcock you’re connected to is turned parallel to the fitting to allow airflow. If there’s a second petcock, ensure it’s set to perpendicular to prevent air from escaping prematurely.
• Open one sprinkler zone at a time and watch as the air blows water out of the heads. Close the zone when water stops spraying, then move to the next until all zones are clear.

Step 4: Finalize the System

• After clearing all zones, turn the flathead screws on the petcocks to a ¾-open position.
• Open the ball valves to the ¾-open position as well to allow for airflow expansion if any water is left behind.
• If your system has a drain in the manifold (sprinkler box), open it.

Congratulations—you’ve successfully winterized your sprinkler system! Stay tuned for our spring guide on how to start it back up safely.

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