Introduction
Worried about burst pipes or costly repairs when freezing temperatures hit? Learning how to winterize your sprinkler system properly protects your pipes, valves, and sprinkler heads from frost damage and saves you from headaches in spring. This complete step-by-step guide shows you exactly how to drain, blow out, and shut down your irrigation system so your lawn stays healthy and your wallet stays happy.
Why Winterizing Your Sprinkler System Matters for a Healthy Lawn
When water sits inside your irrigation pipes during freezing weather, it expands and can crack PVC pipes, burst flexible lines, and damage sprinkler heads and valves. Not only can this cause costly repairs, but a damaged sprinkler system can also delay watering your lawn next season, which stresses your grass and soil.
Taking the time to winterize your system helps you avoid surprise leaks, protects your investment, and keeps your irrigation working efficiently when spring arrives.
Step-by-Step Guide to Winterizing Your Sprinkler System
1. Know Your System Type
Before you begin, check which type of irrigation system you have. Some systems are equipped with self-draining valves, while others require manual or blow-out methods.
✅ Manual Drain: Older systems with manual drain valves that must be opened to release water.
✅ Automatic Drain: Systems with built-in drain valves that open when water pressure drops.
✅ Blow-Out Method: Uses compressed air to push water out of the pipes — recommended for systems that don’t drain completely on their own.
Knowing your system type will help you choose the safest, most effective winterizing method.
2. Shut Off the Water Supply
Locate your main sprinkler shut-off valve — usually found near your water meter or in the basement. Turn it off completely to stop water from entering the irrigation lines.
If your system has a dedicated outdoor shut-off, make sure it’s insulated to protect it from freezing. Use foam pipe insulation or a specialized cover if needed.
3. Shut Down the Controller
Turn off your irrigation timer or controller. Some systems have a “Rain Mode” or “Off Mode” that stops scheduled watering but retains your settings for spring. If yours doesn’t, unplug the controller or shut it off at the breaker.
4. Drain Backflow Preventer
If your system has a backflow preventer (common in many residential setups), drain any water trapped inside.
- Open the test cocks with a flathead screwdriver to let water escape.
- Leave the valves at a 45-degree angle to prevent them from holding water.
This step helps avoid damage to this important device, which keeps contaminants out of your drinking water.
5. Drain the Pipes — Choose a Drain Method
A) Manual Drain:
- Open all manual drain valves at the low points of each irrigation zone.
- Allow water to drain completely.
- Close the valves after draining.
B) Automatic Drain:
- Shut off the main valve.
- Open a sprinkler head or drain cap at the end of each line to release pressure and let water exit through the automatic drain valves.
C) Blow-Out Method (Most Effective for Deep Freeze Climates):
- Rent or use an air compressor with a minimum of 50 cubic feet per minute (CFM) rating.
- Connect the compressor to your system’s blow-out port using the right fittings.
- Set the pressure:
- PVC pipes: Do not exceed 80 PSI.
- Poly pipes: Do not exceed 50 PSI.
- Blow out one zone at a time.
- Start with the zone farthest from the compressor and work your way closer.
- Run the compressor until no more water sprays from the heads.
- Repeat for each zone.
Important: Always wear safety goggles and stand clear of sprinkler heads while blowing out. Never leave the compressor unattended.
6. Insulate Above-Ground Components
Wrap any exposed pipes, backflow preventers, or valves with foam insulation or specialized covers. Even after draining, small amounts of residual water can freeze in these parts, so insulation provides extra protection.
7. Check for Leaks or Repairs
While winterizing, inspect pipes and sprinkler heads for cracks or damage. It’s easier to schedule repairs before spring, so your system is ready to go when the weather warms up.
Common Mistakes to Avoid
Mistake 1: Forgetting to Shut Off the Water Supply
Solution: Always close the main shut-off valve first to prevent new water from entering the system.
Mistake 2: Using Too Much Air Pressure
Solution: Never exceed recommended PSI. Excess pressure can burst pipes or blow sprinkler heads off.
Mistake 3: Leaving the Controller On
Solution: Shut down the timer or put it in “Rain Mode” to avoid accidental watering cycles during winter.
Mistake 4: Ignoring Above-Ground Parts
Solution: Always insulate exposed valves, pipes, and backflow preventers to guard against freezing.
Mistake 5: Skipping Zones During Blow-Out
Solution: Always clear every zone to prevent trapped water from freezing and causing hidden damage.
Extra Lawn Care Tips & Hacks
✅ Mark Sprinkler Heads: Use small flags or markers so you can easily locate heads in spring for maintenance or replacement.
✅ Use Quick-Connect Fittings: Installing quick-connect blow-out fittings makes future winterizing faster and safer.
✅ Schedule Early: Don’t wait until the first hard freeze. Start winterizing in late fall when overnight temps consistently drop below 40°F.
💡 Related read: Check out our guide on [how to aerate your lawn] to reduce soil compaction before winter for healthier roots come spring.
Conclusion
Winterizing your sprinkler system is one of the smartest ways to protect your irrigation investment and avoid expensive repairs. By draining your lines, insulating exposed parts, and following the right blow-out method for your system, you’ll keep pipes safe from freezing and ensure your lawn stays healthy season after season.
Bookmark this guide, mark your calendar each fall, and you’ll be ready for stress-free watering when spring returns!