winter•857 words

How to Winterize Your Lawn Sprinkler System: Complete Guide

Learn how to winterize your lawn sprinkler system properly. Step-by-step guide to protect your irrigation from freeze damage this winter.

📺 how to WINTERIZE your sprinklers (the right way) • Princess Cut Lawn Care

📝 Video Highlights & Key Takeaways
"you can skip a fertilizer application but you can't skip an irrigation system winterization you have water in all of your ation pipes and without putting compressed air through them that water will remain in the pipe"
— Princess Cut Lawn Care

Key Points:

  • •You must winterize your irrigation system before the first freeze of the year to prevent water expansion damage.
  • •Start by shutting off the main water supply valve and clearly marking it as the irrigation valve for future use.
  • •Use an air compressor with at least 20 CFM capacity - pancake compressors lack sufficient volume to properly clear pipes.
  • •Keep air pressure between 50-80 PSI maximum to avoid damaging irrigation components.

Pro Tips:

  • 💡Small pancake compressors create a false sense of security by pushing air across the top of pipes while leaving substantial water at the bottom that can still freeze and cause damage.
  • 💡Look for a blowout port on your backflow prevention device, or remove the backflow cartridge entirely if you have a Wilkins 375 model with a dedicated blowout port.
  • 💡Consider hiring a professional contractor instead of renting expensive tow-behind compressors, as it's often more cost-effective and they have proper equipment.

Quick Answer

Winterizing your lawn sprinkler system involves draining all water from pipes, valves, and sprinkler heads to prevent freeze damage. This process typically includes shutting off the water supply, draining the system using compressed air or manual methods, and insulating exposed components[1].

Detail view of how to winterize lawn sprinkler system technique on residential lawn

Key Takeaways

  • Winterize before the first hard freeze (typically when temperatures drop below 28°F)
  • Three main methods: compressed air blowout, manual drain, or automatic drain
  • Shut off water supply and controller before starting the process
  • Insulate backflow preventers and above-ground components
  • Consider professional service for complex systems or if you lack proper equipment

Why Winterizing Your Sprinkler System Matters

Freezing water expands by approximately 9%, creating tremendous pressure that can crack pipes, damage valves, and destroy sprinkler heads[2]. Even small amounts of trapped water can cause expensive repairs come spring. Most irrigation system damage occurs when homeowners skip winterization or perform it incorrectly[3].

The investment in proper winterization—whether DIY or professional—typically costs far less than repairing freeze damage, which can run into hundreds or thousands of dollars depending on your system's complexity.

Step-by-Step Winterization Process

Method 1: Compressed Air Blowout (Most Effective)

This method requires an air compressor capable of producing 20-80 CFM depending on your system size[4].

  1. Turn off the water supply at the main shutoff valve
  2. Set controller to "rain" or "off" mode to prevent accidental activation
  3. Connect air compressor to the system's drain valve or test cock
  4. Activate each zone manually while applying compressed air (30-50 PSI for spray heads, 30 PSI for drip systems)
  5. Blow out each zone until only air comes from sprinkler heads (typically 2-5 minutes per zone)
  6. Disconnect air compressor and close all valves

Method 2: Manual Drain Method

If your system has manual drain valves at low points:

  1. Shut off water supply and controller
  2. Open all manual drain valves located at system low points
  3. Activate each sprinkler zone to help gravity drain remaining water
  4. Leave drain valves open throughout winter

Method 3: Automatic Drain System

Some newer systems include automatic drain valves that open when water pressure drops[5]:

  1. Turn off water supply
  2. Run each zone briefly to relieve pressure and activate automatic drains
  3. Verify all zones have drained by checking that sprinkler heads are empty

Protecting Above-Ground Components

Backflow Preventer Care

Backflow preventers are particularly vulnerable since they're typically above ground[1]. After draining your system:

  • Remove test cocks and relief valves if possible
  • Wrap the unit in insulation or specialized covers
  • Store removable parts indoors in a labeled bag
  • Never use plastic bags directly against metal components (condensation risk)

Controller and Valve Box Winterization

  • Switch controller to "off" or "rain" mode
  • Install a rain sensor if you don't have one (prevents accidental activation during winter thaws)
  • Ensure valve boxes have adequate drainage
  • Check that valve box lids fit securely[6]

Timing and Regional Considerations

Winterization timing varies significantly by geographic location. In northern climates, complete winterization before nighttime temperatures consistently drop below 32°F[2]. Southern regions may only need partial winterization or protection of sensitive components.

Optimal timing by region:

  • Northern states: Late September to early October
  • Midwest: Mid to late October
  • Southern regions: November to December (may only need backflow protection)

Monitor extended weather forecasts rather than calendar dates, as unseasonable temperature drops can catch homeowners unprepared[3].

When to Call a Professional

Consider professional winterization if:

  • Your system lacks proper drain valves
  • You don't own a sprinkler winterization kit or adequate air compressor
  • The system includes complex zones with different pressure requirements
  • You're uncomfortable working with compressed air equipment
  • Previous DIY attempts resulted in incomplete drainage

Professional services typically cost $75-150 but include equipment, expertise, and often a service guarantee[4].

Preparing for Spring Startup

Before ending your winterization:

  • Document any issues discovered during the process
  • Note which sprinkler heads need adjustment or replacement
  • Store removal parts (like backflow test cocks) in clearly labeled containers
  • Schedule spring startup inspection to check for winter damage[5]

Conclusion

Proper sprinkler system winterization protects your irrigation investment and ensures reliable performance next growing season. Whether you choose compressed air blowout, manual draining, or professional service, the key is completing winterization before sustained freezing weather arrives. Start planning your winterization strategy now, gather necessary equipment or service contacts, and monitor weather forecasts for optimal timing. Your lawn and your wallet will thank you come spring.

Sources

  1. Colorado State University Extension - Irrigation system winterization and freeze protection guidelines

2. University of Nebraska-Lincoln Extension - Turfgrass irrigation management and seasonal maintenance

3. Rain Bird Corporation - Professional irrigation system maintenance and winterization research

4. Irrigation Association - Industry standards for irrigation system maintenance and winterization

5. Michigan State University Extension - Landscape irrigation system management and freeze protection

6. Consumer Reports - Home irrigation system maintenance and cost analysis

Related Video

📺 How To Winterize Your Sprinklers • The Broomfield Channel

📝 Video Highlights & Key Takeaways
"One thing that people often overlook is the fact that all of these ball valves including the small ball valves on these test cocks need to be half open or in other words turn to a 45 degree position and they need to be left that way for the winter."
— The Broomfield Channel

Key Points:

  • •Start by shutting off the water supply to the sprinkler system at the basement shut-off valve and opening the drain screw.
  • •Drain the backflow preventer by opening the test cocks with a quarter turn using a flathead screwdriver.
  • •Open the drain valve in the valve box to drain water from the downstream side of the system.
  • •Leave all ball valves in a 45-degree position throughout winter to prevent water from getting trapped and causing cracks.

Pro Tips:

  • 💡Put a bowl under the indoor drain valve before going outside to break the siphon, as more water will flow back once the outdoor valves are opened.
  • 💡All ball valves must be positioned at 45 degrees during winter because fully open or fully closed positions can trap water and cause valve damage.
  • 💡Never blow compressed air through the backflow preventer itself - always connect downstream to avoid costly damage to the device.

Checklist: How to Winterize Your Lawn Sprinkler System: Complete Guide