Lawn Sprinkler Winterization

Date Published: October 5, 2022

Fall is finally here! For Coloradans, that means leaves changing colors, corn mazes, football games, seasonal pies and more. It also means that that cold CO weather is on its way back.

As homeowners, it is important to be prepared and protect your property from the often times harsh weather. For those who own sprinkler systems, it is imperative to have your system winterized before the freezing temperatures hit.

Lawn sprinkler systems are not cheap. So staying on top of annual winterization is a key way to protect this valuable asset.

Why Winterization?

When in regular use, a sprinkler system will always have residual water left over in its piping and sprinkler heads between cycles. Once freezing weather hits, any remaining water will freeze, causing expansion. This frozen, expanding water has nowhere to move, so it exerts pressure throughout the system, causing cracking, breaking and bursting.

As many homeowners know, sprinkler systems can be very complex, consisting of different valves, regulators, and piping that will run throughout a property. The more complex your system, the more vulnerable it may be.

Sprinkler system manifold

The manifold of a sprinkler system. Image sourced from:

One cracked sprinkler head might be a simple enough repair. But what happens when multiple breaks occur throughout the system, leaving it inoperable? Or what happens when the manifold (which is the main regulator that distributes water throughout the sprinkler system) cracks or bursts? Now you have a pretty serious repair operation on your hands, which may even involve digging underground to make the necessary fixes.

How do we avoid this headache? The solution is simple – lawn sprinkler winterization.

When Do I Winterize My Sprinkler System?

For Colorado residents, lawn sprinkler winterization should generally occur around October. However, there is some wiggle room on that because CO has been known to have some pretty warm Octobers.

Your best bet is to keep an eye on the weather forecasts. You should try to have the whole system ready to go before the temperature hits freezing at night.

Being aware of your grass dormancy period is also a great way to plan for winterization. In places with cold weather climates such as Colorado, grass will transition into a dormant stage when soil temperatures drop below approximately 45 degrees. Grass dormancy is a natural period that grass undergoes in order to conserve water and nutrients during times of more hostile weather.

Dormant grass

Dormant grass. Image sourced from:

Finding out when your grass goes dormant can help you determine when to carry out winterization. When your lawn starts to turn a uniformly tan or brown color, this likely means that the soil temp is dropping, and winterization is just around the corner.

How Lawn Sprinkler Winterization Works

When winterizing an irrigation system, the overall goal is to clear all the standing water out of the system. The most tried and true method is utilizing compressed air to “blow out” the lines. While there are other draining methods, the blow out method is generally the most effective technique because it ensures that all liquid will be cleared from the system.

Lawn sprinkler winterization

Image sourced from:

There are many professional lawn care services that can get the job done. However, if you are a DIY kind of person, it is possible to carry out this process on your own with the right tools and knowledge.

  1. The first step is to shut off your main water supply. Once that is shut off, you’ll want to open up the main hose bib or drain located on the piping section that connects the main water supply to the irrigation system. This will empty out any excess water that came from the main.
  2. Once that is all cleared out, you can hook an air compressor to the sprinkler system. The compressor should be attached after the backflow preventer (aka pressure vacuum backflow device). Note: for common residential water lines that are 2 inches or less, a compressor that produces air 80-100 cubic feet per minute (CFM) is recommended.
  3. Make sure that the isolation valves before and after the backflow preventer are closed.
  4. Starting at the farthest sprinkler zone from the home (or highest in elevation from the home), start to send compressed air through each zone, one at a time. Blow out each zone until no more water is coming out of the sprinkler heads. Note: stop blowing air once the zone is cleared to avoid damaging the irrigation lines.
  5. Once each zone is cleared, shut off and disconnect the air compressor.
  6. Open and close the backflow preventer isolation valves to let out any remaining air pressure and/or built up water.
  7. Open up the test cocks to drain any remaining water.
  8. Leave the isolation valves at a 45 angle so that any traces of water in those valves will drain out.
sprinklers being blown out during winterization process

Sprinkler head being blown out. Image sourced from:

There are plenty of solid online articles and videos that can give you extensive details on how to perform a lawn sprinkler winterization. However, if you are uncomfortable with the process in any way, it’s never a bad idea to hire an irrigation specialist. It’s always better to pay a little extra up front then to deal with costly repairs from a DIY-related mistakes.

Inspecting Sprinkler Systems

During our standard inspections, we test sprinkler systems when possible. If the temperature permits, we will run the system. However, if the weather is too cold, we are only able to perform a visual inspection.

We inspect valves and sprinkler heads where possible, and always try to locate the sprinkler system shut off. If we observe any defects or damage we will be sure to inform our clients and recommend further evaluation by an irrigation specialist. Additionally, our inspectors will discuss with the client the importance of regular sprinkler maintenance and periodic winterization.

Are you in need of a home inspection? At Scott Home Inspection, we provide a reliable, high quality and unbiased assessment of all aspects of a home (including, of course, lawn sprinkler systems). Contact us today for more info or to book your inspection today.

Be Kind, Winterize!

One of the best ways to prevent unnecessary damages is to stay on top of routine maintenance. That’s why we take periodic trips to the dentist or why we get oil changes for our cars on a recurring basis.

There are lot of things we can’t control, but this is one thing we can control. So whether you do it yourself or hire out to a pro service, make sure to stay on top of your annual lawn sprinkler routine. Be kind to your lawn sprinkler system, winterize!

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About the Author: Chris Kimmel

Chris Kimmel worked as an Associate Home Inspector for two years, handling numerous services including sewer scope inspections, pest inspections, mold air sample testing, radon testing, and water quality testing. Chris now works with Scott Home Inspection as a Content Writing Specialist.

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