As colder weather steadily creeps in and fall fades to winter, it’s time to start putting things to bed for the season. We call this “blow-out season” because if any water freezes in your sprinkler pipes, it will expand, which can cause them to break or burst.

This is why it’s important to “blow out” any remaining water before things get too cold and start freezing. Smart maintenance during the fall can help prevent costly repairs down the road. So, if you want to prevent winter blowouts, follow these tips to winterize your sprinkler system this fall.

Winterizing Your Sprinkler System

Can you winterize your own sprinkler system? Yes, you can if you have access to some specialty equipment. That said, it’s important to be cautious and follow all instructions carefully to avoid hurting yourself or damaging your sprinkler system.

Manual Procedure

If you have a manual drain valve or drain cap, be sure to wear eye protection before completing this task, as these systems are pressurized and could cause injury if opened before the pressure is relieved.

1. Turn off your sprinkler system’s mainline shutoff valve.
2. Open one of the control valves (manually or electronically from the timer) to relieve pressure on the mainline.
3. SLOWLY open the manual drain valve.
4. Repeat this procedure for ALL manual drain valves on your sprinkler system mainline.

Automatic System Procedure

The automatic drain valve is a spring-loaded device that is installed on the sprinkler heads or pipes. Automatic drain valves will remove water from the system every time it is shut off. As such, you should not need to manually intervene. Still, it’s important to check for excessive puddling on the surface of the soil, which could indicate one of the drains has become stuck open.

Blow-Out the Lines

Make sure you wear eye protection during this process and be careful to avoid creating excess pressure, which could damage your system and cause injury from flying debris. DO NOT stand over any irrigation components during air blowout. The air pressure should not exceed 50 pounds per square inch (psi).

For best results, it is recommended that you use a large compressor (50-70 gallons) that can keep a continual flow of pressure of 185 cfm or greater. The compressor should be regulated to provide 75-85 psi, depending on how big the lines or zones are in your system.

If you do not have the right equipment for this procedure and are worried about doing something wrong, you should contact a professional to provide the service for you.

If you do intend to take care of the blowout yourself, make sure you OPEN ONE VALVE BEFORE STARTING THE AIR COMPRESSOR, as this will help balance the pressure, so you don’t damage the system or blow any head apart.

Additionally, keep in mind that this process will create heat in the lines, which needs to be regulated so as not to warp any of the pipes or fittings. You DO NOT need to blow every single drop of water out. Make sure you don’t run the air too long with gear drive rotors, as it can heat the rotor wiper seal and melt the rotor head together, which will require costly repairs come spring.

Blow-out procedure when activating valves from a controller:

1. Close the mainline sprinkler shutoff valve.
2. Relieve the water pressure on the mainline by activating a circuit or zone from your controller. Make sure you activate the circuit that is furthest from the air connection before blowing air into the piping. 
3. Attach the air compressor hose to a blow-out adapter.
4. Set the pressure regulating valve on the compressor to 50 psi.
5. Turn the compressor on and gradually increase the airflow until the sprinkler heads pop up. The amount of airflow or volume needed will depend on the length of your pipes and the number of heads. 
6. DO NOT blow any circuit for more than 2 minutes at a time, as heat from the compressed air can damage the pipes and other components. 
7. Switch to another station or zone by advancing the timer to the next circuit. DO NOT turn the controller off at any time during this process until the compressor is shut off. 
8. To ensure adequate drainage, repeat this cycle two or more times, activating each one from the timer until nothing more than a fine mist appears from the heads. 
9. After you have blown out all zones, leave one zone on while you shut off the compressor. 
10. Unhook the air compressor from the adapter.
11. Turn the timer to “OFF”.

Blowout procedure when activating valves manually:

This process is only to be used if your system doesn’t have electric valves connected to a controller. 

1. Close the main shutoff valve.
2. Slowly open the manual shutoff valve handle on one of your zone control valves to relieve water pressure on the mainline. 
3. Attach the air compressor hose to a blow-out adapter.
4. Set the pressure regulating valve on the compressor to 50 psi.
5. Turn on the irrigation zone you want to blow out.
6. Turn the air compressor on and gradually increase the flow of air until the sprinkler heads pop up. Again, the amount of airflow and volume needed will depend on how long your pipes run and how many heads there are.
7. DO NOT blow any zone for more than 2 minutes, as the heat created by the air compressor can damage components. 
8. After 2 minutes, turn the compressor off and allow all the air to completely purge from the compressor tank and sprinkler system. 
9. Turn on the next irrigation control valve you want to blow out.
10. Turn off the last control valve you just blew out. 
11. Repeat this process until you have completed two or more blowout cycles per zone. If the process was successful, you should only see a fine mist blowing from each head. 
12. Turn the air compressor off and allow any air left in the storage tank or irrigation components to disperse before touching the air hose or valves.
13. Unhook the compressor from the adapter.

Additional Winterizing Tips

After your system is fully drained, you’ll want to take a few extra steps to fully winterize your system. This includes shutting off the water source and insulating your valve boxes and backflow preventers. Any other steps you may need to take will depend on your system. If you aren’t sure what to do, it’s best to contact a professional to handle winter maintenance for you. 

A smart WiFi-based timer, like the Rain Bird ARC Series Controller, can help as it provides numerous features that can help you more easily maintain your sprinkler system, such as:

• Automatic seasonal adjust to match the season, weather, and temperature
• Notifications and alerts for freeze warnings
• Easy control of all zones (or stations)
• Rain/freeze sensor, master valve, and pump start relay circuits
• And more!

Professional Sprinkler Winterization

Though you can winterize and blow out your sprinkler system on your own, it is a tedious process and should be handled with care. If you have any concerns about handling this process yourself, it is advised that you contact a professional to take care of your winterization maintenance for you.

Though having a professional handle this task for you might seem like an added expense, it can save you time and money in the long run. If you don’t perform winter maintenance adequately yourself, it can damage your system, which will require costly repairs come spring. So, having a professional handle the maintenance for you can end up saving you from more expensive repairs down the road.

Whether you hire a professional or handle it yourself, winterization of your sprinkler system is an essential step that should not be overlooked. Seasonal maintenance can go a long way toward extending the life of your system and protecting it from damage, so everything is ready when spring arrives.