How to Winterize a Sprinkler System

By: Contributors  | 
A working sprinkler shooting water onto wet grass.
It is vital to protect your outdoor property during winter — especially your sprinklers. Malorny / Getty Images

Those living in northern areas that receive frost and snow know how important it is to protect their outdoor property to ensure that it's still operational when the temperatures rise in the spring. Near the top of that to-do list, you should add: "Winterize sprinkler system".

Many homeowners don't know how important this job is to the ongoing functionality and performance of your sprinkler system — and they pay the price for that ignorance! Fortunately, in this article, we'll not only explain how you can blow out draining in your sprinkler system but also reveal the consequences of avoiding this task.


Why is Winterizing So Important?

As the cooler months approach, it's crucial to prepare your garden and its maintenance systems for the harsh conditions. Winterizing your sprinkler system is a key aspect of this preparation. The process involves draining water from the pipes, valves, and sprinkler heads to prevent freezing and bursting.

This step is vital because water expands when it freezes, which can cause serious damage to your sprinkler system. How much could it cost to repair or replace your sprinkler system in the spring? Big bucks!


How to Winterize Your Sprinkler Systems

To winterize your sprinkler system and get it ready for the cold winter months, follow these steps:

  1. Turn the water supply off. Depending on how your system was built, you will be able to find the main valve (sometimes called manual drain valve or master shut off valve) in the basement, utility room, or outdoor shed.
  2. Manually drain the water from the irrigation system. Reduce the pressure flowing through your system's pipes by opening the hose bib. Catch the water running from the pipes with a large bucket. Remember the water is going to spurt due to the pressure in the pipes, so you're going to get wet [source: Zawacki].
  3. Rent or purchase an air compressor from your local equipment-rental yard. Charge the compressor. Most compressors can charge up to 120 pounds per square inch of compressed air, but never charge it that high. Using so much pressure may damage your sprinkler system. Most experts recommend that you charge the compressor to 60 pounds per square inch [source: Higgins, Swift].
  4. Attach the compressor to the hose bib, after checking that the compressor is off. You may have to be creative to get a secure seal between the hose bib and the compressor, because the fittings almost never match.
  5. Turn on the compressor and empty the hoses, starting with the furthest zone from you and working your way to the nearest. Keep the sprinkler on for approximately two minutes in each zone. Watch the water sprinkling from the system. When the remaining water turns from mist to air, it's time to move onto the next zone. Once you have finished with the zone nearest you, you have blown out your sprinkler system [source: Zawacki].
  6. Finally, you'll want to insulate any components of your sprinkler system that are exposed above ground. Valves and backflow preventers should be insulated to protect them from freezing temperatures.


Utilizing 'Rain Mode' and Backflow Isolation Valves During Winterization

Many modern sprinkler systems feature a 'rain mode' setting, which can be particularly useful during the winterization process. Activating 'rain mode' allows the system to shut off its active watering schedule without altering the programmed settings, making it a convenient option for seasonal transitions.

Additionally, attention should be given to backflow isolation valves. These valves are crucial for preventing contaminated water from flowing back into the main water supply. During winterization, ensure that these valves are properly secured and insulated, as they play a vital role in maintaining the system's integrity and protecting water quality.


The Role of Compressor Valves, Drain Outlets, and Air Vents in Automatic Draining

The use of a compressor valve is integral in the 'blow-out' method of winterizing sprinkler systems. This valve allows compressed air to flow through the pipes, effectively clearing out any remaining water. Meanwhile, drain outlets in the system should be checked to ensure they are clear and functioning properly, as they allow water to exit the system during the automatic draining process.

Additionally, air vents within the system should be inspected to confirm they are open and unobstructed. These vents play a critical role in the automatic draining process by allowing air to circulate through the system, which helps prevent water from being trapped and subsequently freezing.


Regular Maintenance Checks Before Winterization

Before starting the winterization process, it's important to perform a thorough maintenance check of your entire sprinkler system. Look for signs of wear and tear, such as leaks, broken sprinkler heads, or damaged pipes. Addressing these issues before winter sets in is crucial.

Repairs done in advance can prevent further damage caused by freezing temperatures. This proactive approach not only ensures the longevity of your sprinkler system but also maintains its efficiency for the next season.


Consequences of Neglecting Winterization

Failing to winterize your sprinkler system can lead to various problems. The most common issue is the bursting of pipes due to the expansion of frozen water inside them. This not only disrupts the functionality of your system but also requires expensive repairs. The average cost of replacing a single backflow device is about $300, but could skyrocket to about $1,000!

Additionally, the damage caused by freezing can extend to other parts of your garden, affecting the overall health and appearance of your landscape. In severe cases, water leakage from burst pipes can also lead to soil erosion and foundation damage to your property.


Professional Assistance and Its Benefits

While winterizing your sprinkler system can be a DIY task, seeking professional assistance has its merits, especially for a complex or large-scale irrigation system. Professionals have the expertise and the right tools to efficiently winterize your system, reducing the risk of damage.

They can also provide valuable insights and recommendations for your specific landscape needs. Additionally, many professional services offer springtime checks and maintenance, ensuring your sprinklers are in top condition for the new growing season.


This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.