Sprinkler Blowout

Blowing out the Fog

Photograph by Cody Owen. (c) Green by Nature 2019

ground to freeze and cause a whole lot of damage to your irrigation system.

Even systems that tend to drain most of the way, still need to be winterized because anywhere water might pool up, it will eventually freeze and split pipes and break valves.

The most important element of your irrigation system that needs to be protected is your backflow device. These units are especially sensitive to freezing, even though they are metal. You might think your backflow can handle a little frozen water, but the reality is, brass – which is what double check valves are constructed out of – is very brittle. Plastic expands and “gives” a little, but there will be no such mercy when it comes to your backflow.  

Having your system properly drained is a serious issue that only a licensed professional should handle.  

What is a Sprinkler Blowout?

A sprinkler blowout is a process where compressed air is simply forced through the lines to expel all the water.

This process typically produces a fog like that shown in the photos. 

Fog is an important part of the process. It shows there is enough volume of air coming through at the right pressure forcing the water into tiny droplets. 

Some people try blowing out their own using their little compressors they have in their garages.   

on thought that occurs to many homeowners is that because their small hobby compressor produces 90 psi or more, that it is more than adequate to push the water out of their lines, and in many ways, it appears to work. The problem is not pressure, its volume. That is why landscape companies are towing around those giant compressors. In reality, the storage tank on one of those compressors is only a little larger than the average $100 compressor you can pick up from your local box store.

The difference is volume. The typical tow behind compressor supplies 185 cubic feet of air per minute. Let’s break that down a little further, that’s 3 cubic feet per second! The typical hobby compressor delivers between 2 and 10 cubic feet per minute, 10% of the capacity needed to do the job.

Sprinkler Fog

Photograph by Cody Owen. (c) Green by Nature 2019

So a 10 station system might cost $80, a $50 base charge and $5 each for 6 additional valves.

Be careful with who you hire to perform the work. While a homeowner can winterize their own system, in the State of Oregon, only a licensed professional such as a plumber or landscape irrigator can winterize your sprinklers. This is important because if the work is not done correctly, there is no protection for the consumer if that results in damage.

People who are blowing out sprinklers without a license are breaking the law, which by definition, makes them unethical. I understand that you might have a friend who has a compressor and you offer to pay them $20 bucks, beer, and pizza to get the job done. Hey, that’s between you and your friend.

I’m talking about unlicensed businesses who should not be offering this service to the public under the law.  And what I am really concerned about is you not having a bad experience.  

What Does a Blowout Service Typically Include? 

 Typical service includes:

•  Shutting off the main valve
• Closing the isolation valves and draining the backflow
• Expulsion of water using high volumes of compressed air
• Turning off the irrigation timer (when access allows)

The entire process typically takes 20-30 minutes for most residential systems. 

Scheduling

If you are not properly equipped to handle your own blowout, it’s best to get on the list of a licensed provider right away. Blowout season comes fast and hard in Central Oregon and the wait time to get on someone’s schedule can explode out to several weeks to a couple months. 

When Should I have My Sprinkler’s Winterized?

Typically you want to have your sprinklers winterized sometime in October, usually between the middle to end of the month. If your service provider can’t make it by then, don’t worry. Most systems should be fine up into December, barring an unexpected and untypical change in weather.

Some snow and freezing won’t affect most systems at first because the pipes are typically buried several inches in the ground and it takes time for the ground to freeze. So at first, the ground insulates your pipes. But only for so long. 

In the mean time, while you are waiting to have your sprinklers winterized and blown out, you can take a few preventative steps of your own. You can: 

• Turn off your irrigation main valve
• Turn on a station valve to relieve pressure in the main line and allow it to drain
• Turn off your isolation valves on the backflow device, and put a layer of insulation over the top if there isn’t any already there 
• Shut off your irrigation clock

Can Green by Nature Winterize My Irrigation System?

Yes! But be sure to get on our list soon because it always fills up quickly. Green by Nature winterizes hundreds of properties every year. We are licensed and highly experienced providing quality winterization services. If you would like to get on our list, click the link below and fill out a service request and we will get that scheduled as soon as possible for you.

Thanks for reading!