Winter Irrigation

What does winter irrigation look like? Is it right for you? Our goal is to give you information about winterizing your irrigation system so you can decide whether or not to winterize.  

What is winterization? At it’s core, winterization means preparing your irrigation system for freezing temperatures so that they do not damage your system . What would possibly damage your irrigation system? The primary way is for water in your irrigation to freeze and expand, and it’s the expansion that breaks things, i.e. backflow preventers, valves, pipes, emitters, etc.. With that said, it’s not absolutely necessary to winterize your irrigation, and with the information in this article, you’ll be able to make the decision that’s best for you.   

Your irrigation system is the life blood of your landscape. Without water during the growing season, you most likely won’t have living shrubs, trees, flowers, gardens, etc.. But with a properly designed/working system, you’ll set your landscape up for success. It is with the understanding that irrigation systems are central to the success of your landscape that we even bother talking about winterization.   

The first topic to talk about is the weather. In order for irrigation systems to freeze & break, the weather must be at or below freezing temperatures for a long enough time period to do so. Here are the average monthly temperatures in Greater Prescott.   

As this chart points out, on average, the nights are below freezing while the days warm up well above freezing. The first thing to point out is that, aside from extra cold winter storms, we don’t receive sustained freezing temperatures that cause damage to irrigation systems. This doesn’t mean that there’s no reason to winterize, but it’s one of the factors to be aware of. This doesn’t immediately mean that you don’t have to winterize, so keep reading before you cast your final vote.   

The second thing to point out has to do with the amount of precipitation we receive. Greater Prescott receives on average 7” to 8” inches of rainfall and 12” to 13” of snowfall during this period, making an average total of 20” of precipitation. For established landscapes, the shrubs & trees will have no problem finding water. On top of that, landscape shrubs & trees slow their growth significantly, which means they need less water. At this point you may be asking yourself, “what if we have a warm & dry winter, what can I do to get my landscape water?” If you winterize and we don’t get precipitation, we recommend having us re-start your system; it’s that simple.   

After we’ve considered what’s in the chart, let’s talk about what could potentially happen if you don’t properly prepare for winter irrigation. 

• Nothing. Nothing would freeze. Nothing would break. Everything would work as usual. This is the ideal outcome.  
• The backflow preventer could crack, which is the single most expensive irrigation component on most people’s systems.  
• Valves could crack from having frozen water in them, requiring the valves to be replaced.  
• The poly or PVC irrigation pipe could crack from having frozen water inside, requiring the poly pipe to be replaced.  
• The emitters could crack and require emitters to be replaced.

The benefits of winterizing your system are straightforward; the probability that backflow preventers, valves, water lines, emitters, etc. will freeze and break significantly declines. What are the benefits to not winterizing your system? You can guarantee that your landscape can be watered if you choose. One thing we want to point out is that if you plan on leaving your system on during Winter, then we can install heat tape around certain components to keep them from freezing. We simply need to locate a power source near your irrigation manifold and run the heat tape to those components. If there is now power source nearby, you may have to have an electrical outlet run to the manifold before we can install the heat tape. The cost starts at $350 and could be higher than $2,000.   

We’ve given you a lot of information but we’ve yet to tell you what’s required to properly winterize your system.  

• A ball valve in between the main water source and irrigation manifold. This allows isolation between the irrigation manifold and the main water source.  
• The irrigation manifold (the irrigation box in the ground with the valves inside) needs a drain. This is effectively a hose bib that allows water to escape the valves & pipe. While this will not drain the entire system of water, draining a small amount of water provides room for expansion if freezing does occur.   
• An insulation pillow is a great addition inside the irrigation manifold; think of it like an extra piece of insurance. 
• Turn off your irrigation timer, which is the easiest part of winterizing. 

To finish up this article, when you setup your irrigation system properly, the probability that your system will have freeze damage is significantly decreased. In all the years we’ve been doing winterizations, we have not had one issue. Thank you for reading this article and we trust that you’re now able to decide if you’re going to winterize or not.   

Pricing 

Assessment to learn if your system is setup properly – $75 

Basic Irrigation Package – $360 – Winterization and Spring Start Up 

Bronze Irrigation Package – $520 – Winterization, Spring Start Up, 1 Seasonal Inspection  

Silver Irrigation Package – $660 – Winterization, Spring Start Up, 2 Seasonal Inspections 

Gold Irrigation Package – $1,085 – Winterization, Spring Start Up, 5 Seasonal Inspections 

Frequently Asked Questions  

Question: What if we have an exceptionally warm & dry winter?  

Answer: Assuming that your system has been winterized, in the case of a warm & dry winter, we can come back out to your house and make it operational. This would likely incur a cost, but if it’s in fact warm & dry, we would recommend having your irrigation turned on.   

Question: Do I need to blow out my irrigation pipes?  

Answer: In the Prescott area, it is not necessary to blow out all the irrigation lines with compressed air. As long as the irrigation manifold is isolated from the main water supply line with a ball valve, all that is necessary is to be able to drain out the backflow preventer and irrigation manifold (the valves in the ground). This is why it is important to have a drain installed on your irrigation manifold. Once those “hard pipe” components are drained, you will not likely have any issues with things freezing. Having grown up in Prescott and winterized irrigation systems for decades, this method has served us well.  

Question: What happens to my shrubs & trees if I turn off my irrigation system?  

Answer: If you winterize your system and stop watering your shrubs & trees, then in most cases you won’t see any change, nor will the shrubs & trees experience any issues. Shrubs and trees will likely receive precipitation to feed from, and if it’s warm and dry, then we can re-start your system. Also, growth slows significantly during winter, which means their need for water also decreases significantly.  

Question: What sort of warranty comes with my winterization?”  

Answer: In all the years we’ve been winterizing systems, we have not had one issue.  

Question: What if my shrubs & trees are newly planted?  

Answer: We recommend leaving your irrigation system turned on because newly planted shrubs & trees need water. Another option is winterizing your system and watering with a hose.  

Question: If I don’t winterize, what is the best time of day to water?  

Answer: We recommend in the heat of the day, so start around 1:00pm.  

To read about FAQ for pest control, read this article.

Lastly, we highly recommend Watter’s Garden Center, Mortimer Nursery, or Prescott Valley Nursery as great places to both purchase shrubs & trees but to also ask questions because these are the experts.