Last Updated on October 26, 2026
When leaves start to turn brown and temperatures drop, it’s time to winterize your irrigation and underground sprinkler systems. As a property owner or facility manager, you can protect your property from costly repairs with an irrigation blowout and shutdown.
The best time to do it? In the late fall, right around the time of the first frost and before the ground and your irrigation pipes freeze.
Winterizing an in-ground irrigation system is the final piece of maintenance before shutting down until spring. The job is usually inexpensive, quick and important. Why? Any water remaining in an irrigation system has the potential to freeze, expand and damage the system, resulting in costly repairs.
The Importance of Irrigation Winterization
Irrigation systems are valuable investments that help keep your landscape beautiful and functional throughout various weather patterns. Unfortunately, since they’re buried below ground, irrigation systems are extremely easy to forget about — until it’s too late. Then you have an expensive mess on your hands.
Simply turning off the water isn’t enough to protect your irrigation system in winter.
Winterizing an irrigation system is the process of fully emptying the pipes and shutting down the system. It’s a process that protects the system from damage and wasted water.
What Happens if Irrigation Systems Aren’t Winterized?
In the spring, summer and early fall, small amounts of water remain in the pipes every time an irrigation system runs. When temperatures dip in late fall and winter, any water left inside the system can freeze, weaken pipe walls or cause widespread damage to system components like nozzles, heads and more.
If you forget to perform an irrigation shut down and the pipes break below ground, water can flood the area, damaging plants and nearby structures. And you may not even realize it until spring, when the damage has been worsening for weeks or months. Unexpected repairs like this can strain budgets and cause any other projects to come to a grinding halt.
How to Winterize Your Irrigation System: 3 Methods
While some systems may be equipped with automatic draining, others have to be manually drained or blown out using compressed air. In this section, you’ll learn the basics of each irrigation shutdown method to understand which approach may be best for your property.
Manual Draining
Manual draining involves simply opening the manual valves and letting the water drain out. These valves can generally be found at the ends of piping and at low points.
If you have check valves on your irrigation system, you may need to raise the sprinkler heads to get the water out of them.
Once all the water has emptied, you can close all the valves.
Automatic Draining
Some irrigation systems are equipped with automatic draining systems. These systems will automatically engage when the water pressure falls below a certain threshold.
To trigger the automatic draining system, simply shut off the water supply and then run one of the sprinklers until the water pressure falls below the threshold. You can then turn off the sprinkler and let the system drain.
Afterward, you should drain any water between the shut-off valve and backflow device as well as the sprinkler heads if they are equipped with check valves.
Irrigation Blowout Method
The final method uses compressed air to blow out the water from the system, ensuring all pipes are completely empty.
Before using this method, you should confirm that your system can handle the pressure. It’s also important to note that while an irrigation blowout is a fairly simple procedure, it should be done by a professional who will ensure the process protects your system and surrounding landscape.
While not all systems are built the same, traditionally an air compressor able to push 80 up to 185 cubic feet of air per minute (CFM) is enough for residential in-ground systems.
- Learn More: What Air Compressor Size Do I Need?
To use the blowout method, you will need an air compressor, a coupler that fits your irrigation system and safety glasses. Then follow these steps:
- Shut off the water supply.
- Connect the air compressor to the irrigation system using the coupler with a check valve so no water runs back into the compressor.
- Turn on the sprinkler that is furthest from the compressor.
- Close all the backflow valves and open the valve on the compressor.
- Slowly increase the air pressure so that you can quickly shut it off if something goes wrong. Keep going until you see water coming out of the sprinkler. (Do not exceed 50 PSI for polyethylene or 80 PSI for PVC piping.)
- Begin turning on more sprinkler heads, starting with those furthest away from the compressor.
- Turn off each sprinkler head when there is no more water coming from it.
- Once all the sprinklers are empty and shut off, you can turn off the air and disconnect the compressor.
- Open all the backflow and manual drain valves to release the pressure in the system.
- Close all the valves back up.
Precautions to Keep in Mind
Get to Know Your System: Questions to Answer
When choosing a method, or renting air compressors and other equipment, make sure you can answer the following questions. The answers to these questions will help you and your equipment rental provider identify the right equipment.
- Is the application for residential or commercial use? Or is it for a golf course or other athletics facility?
- How many irrigation zones are there? Do you have a map of the system?
- What type of pipe is used in the irrigation system (PVC, polyethylene, etc.)?
Tips for Using an Air Compressor Safely
If using an air compressor, here are some precautions to follow that will help ensure a safe and effective irrigation blowout and shut down.
- Use an air compressor with a cubic feet per minute (CFM) rating of 80-185 for any mainline two inches or less.
- Adjust the outlet pressure on the air compressor down to the lowest possible setting, typically 80 pounds per square inch (PSI).
- Use a pressure regulator at the connection point of the irrigation system to reduce the pressure even lower. Typically, 12 PSI is a good starting point. Then increase the pressure as needed.
- Use the correct amount of hose, typically ¾-inch, and always use whip locks at hose connections for safety. To reduce pressure loss in the hose from the compressor to the sprinkler system, be sure to get the compressor as close to the sprinkler connection as possible and use the shortest length of hose possible.
- Avoid exceeding 50 PSI for polyethylene piping systems and 80 PSI for PVC piping systems. In smaller residential systems, 15-25 PSI will be all the pressure needed to remove water from the system. This is dependent on the size of the pipe, number of heads per zone and total amount of piping per zone.
- Once the compressor is connected to the system, cycle the zones one by one until no more water flows from each zone. Then, move to the next zone. Time in each zone will depend on its size and amount of residual water in the zone.
- Avoid running the compressor without at least one sprinkler control valve open.
Winterize Your Irrigation System Now with Equipment from Herc Rentals
Weather can be unpredictable, and a surprise freeze can leave you scrambling to clear your irrigation system of water before the drop in temperature causes costly repairs. To avoid the pain of unexpected work, drain your irrigation system as soon as it is done being used for the season.
If you need an air compressor or other equipment to perform an irrigation blowout and shut down, contact the experts at Herc Rentals. We’ll help you understand your irrigation system’s needs and find the best equipment for any project. Our towable air compressors come in various configurations and capacities to help you winterize your irrigation system quickly and safely.
Explore our selection of air compressors and tools, or call 1-800-432-6215 to get started today.
