Let’s do an experiment. Close your eyes and picture this scenario:

It’s a sunny afternoon in January. The popular Frank Loesser song swoons “Ah, but baby it’s cooooold outside,” softly in the background as you keep your toes warm by a roaring fire. Children are playing in the snow, bundled up, making a giant snowman, and there is talk of hot chocolate.

It sounds like a picture-perfect winter day, right?

Now picture that same scenario through the eyes of a landscape professional. There is still the same classic winter song, the same fire, and the same hot chocolate. But underneath the mounds of snow and snowmen is an irrigation system that has not been winterized!

As a contractor, you know the cold winter temperatures, ice, and snow are not picture-perfect for an irrigation system. Ice can wreak havoc on sprinkler systems. Beneath the frozen surface, your client’s sprinkler system is hibernating, trying desperately to survive the winter months unharmed.

Come springtime, a damaged irrigation system can cause swampy areas, stressed landscapes, and the possibility of odd odors from stagnant water. These are avoidable headaches you can prevent.

Clients may argue with you that they do not need a professional to winterize their sprinkler system.

“Why spend the money on something I can simply do myself?” they may say. Or, “My system is safe from freeze damages because it’s underground.”

If you were paying attention during science class as a kid, this is where it will finally come in handy. But for those who may have forgotten a thing or two, here is a quick chemistry lesson. When the temperature drops, the liquid form of H 2 O, water, will harden and freeze. When water freezes, it begins to expand. And expanding water can be very powerful, even in small amounts.

Water trapped in confined places, such as pipes, sprinkler heads, backflow prevention devices, valve chambers, and most parts of an irrigation system, can do serious damage in cold weather—it’s a scientific fact. If an irrigation system is not properly drained, homeowners face the risk that leftover water can shatter pipes—especially PVC pipes— though even the more flexible polyethylene material will rupture as well.

Without a doubt, the exerted pressure of expanding ice will damage irrigation components. These damages can be both extensive and expensive. The repair cost usually far outweighs the cost of a professional shut-down. It would make more sense for a homeowner to pay a modest sum to winterize, than to pay a large fee in repair costs.

This is why it’s a good idea to encourage your customers to be proactive. It is rare to find an unwinterized system in a cold climate that survives unscathed through to spring. Many clients may think that only snow will damage their irrigation systems. They will wait until snow is forecasted to think about winterizing. But the water remaining in the system from the spring and summer seasons is really the ultimate killer. Clients don’t realize that winterizing irrigation equipment is a necessity in most parts of the country.

The importance of communication

If you are a contractor in a cold weather state, make sure your customers—reoccurring and new—are ready for the winter season. As soon as frost is predicted, start notifying customers to winterize, whether or not they are on a contract. Do not let their picture-perfect winter day get overpowered by the headaches they will face in the springtime.

“Ultimately, not winterizing could lead to costly repairs to the system, water-wasting leaks, and damages to other nearby property,” said Brent Barkley, product manager of rotors and rotary nozzles at Rain Bird Corporation. “It is even possible that a leak could result in a safety hazard, if ice develops on nearby walkways.”

Many homeowners assume that they only need to disconnect the water supply and turn off the system controller to avoid damages. They do not always think about the range of problems a sprinkler system could develop. It is important that you, the professional contractor, educate them.

“They should leave it to the professionals, because although it’s not too difficult to complete, it’s something that needs to be done correctly,” said Michael Madewell, technical services supervisor at Hunter Industries. “Winterization should really be left to the people who do it for a living.”

If a winterization is done improperly, the risk of freeze damage greatly increases. When a customer tries to save money and uses a compressor from their garage, chances are, they are not getting all of the water out of the system. Communicate with your clients about properly winterizing their irrigation system. They will thank you in the end for looking out for them.

Stacy Derner, one of the owners of Aqua Pro Sprinklers in Watertown, Minnesota, is no stranger to winterizing irrigation systems. For more than a decade, her company has offered this service. According to Derner, in Minnesota, a state known for harsh winters, “if you don’t winterize, it will freeze and break.”

So how does she get customers to remember to winterize their sprinkler systems? She communicates.

“We send out an email and a mailing, giving them a proposed date of when we’d like to stop by,” said Derner. “Nobody wants to be the first though, especially if it’s been a dry fall.”

Typically, this process starts around the end of September. They send pre-existing customers a service date, which varies each year. The dates range from the end of September to anywhere in October. This way, clients do not have to make a mental note to schedule their service. Aqua Pro Sprinklers simply takes away the hassle.

"It's another reason to knock on that client's door, said Madewell. "Spring start-ups and winterizations provide a reason to interface with your target audience"

Using direct marketing is a perfect way to narrow down your customer base and avoid wasting marketing dollars.

John Eggleston of Service First Irrigation in Lansing, Michigan, instructs the contractors he trains to note throughout the year where irrigation systems are located. They then use this information to help directly target customers.

“You’ve got to get in front of those customers who have systems that need to be winterized,” said Eggleston. “There’s no other way to do it.”

Become your client base’s go-to contractor by proactively suggesting beneficial services. Create preferred customer programs, such as seasonal, year-round, or mid-season review services, that include periodic tune-ups and discounts on other services like controller reprogramming and repairs.

When you stay in touch with your customers, it decreases the chances of them shopping around. Maintain close and personal relationships to let them know you are acting in their best interest. Do this, and they will feel like the competition isn’t even worth researching. It’s just good business.

Winterizing steps

Go into each of your winterizations with a game plan. “Have a proactive approach for that customer; they’ll feel very taken care of,” said Madewell.

Break the whole winterizing process down into four main steps: Follow the Pre-check, Disconnect, Open, and Drain plan. This plan can be used on residential properties, as well as commercial sites, to prevent avoidable damages.


During this phase, test the existing irrigation system for leaks, damages, and any other poorly functioning components, like skewed sprinkler heads.

Let your client know the status of their system prior to the long winter months. Repair any damages and return the system to one hundred percent before continuing.

Next, check the system’s controller. If a timed controller is left alone, the normal watering schedule will continue throughout the winter. So it’s important to remember to switch the controller to the off position, and not just to “rain” mode.

During the spring turn-on, the controller may need to be reprogrammed. Make a note of the watering schedule in your client’s file to avoid any confusion come spring.

The final bullet point in the precheck phase is to insulate any aboveground pipes and backflow preventers, as an extra precaution. Use self-sticking foam-insulating tape or foam-insulating tubes.


Now, the most important step in winterizing is to disconnect the water supply at the source and cap it. Winterizing cannot be done if water is still able to flow through the irrigation system.

Depending on if the property is residential or commercial, you may need to consult with facility personal to get the irrigation water turned off. The water supply for residential properties will either come from a pump station or the city. If the water source is a pump station, disconnect the control panel. If it is from the city, simply cut off the source. It usually can be done manually, but sometimes sites have it set up so water can be turned off remotely. Again, note any specific instructions to speed the process along in the spring.

Forgetting to disconnect the water supply will be detrimental. It can lead to the loss of angry customers and potential legal liabilities.


Step three is to open the system valves. Once open, some water may drain out on its own. You will still need to drain the entire system completely, to make sure no water remains.

Drain from the lowest point or points. Let gravity move the water downhill. In this step, you do not need to worry about getting every last drop of water, because there is still a final step to follow.

Water should be drained from the backflow device as well. Do not use compressed air in this component! If possible, remove the backflow preventers, shake the water out of them, and bring them inside to prevent freezing.


The final step is to completely drain the pipes. There are three different draining options: manual draining, automatic draining, or compressed air “blow out.”

The manual drain method can be used when valves are located in common points at the lowest areas on a property. The process simply consists of shutting off the irrigation water supply, opening the manual drain valves, and waiting for gravity to do its job. The major risk of this method is that small pockets of water usually remain in the lines.

Automatic draining is very similar to manual draining. The valves are also located at the lowest points, but will automatically open and drain water if the pressure per square inch (PSI) in the piping is less than ten.

Most automatic systems use check valves to clear water. According to Madewell, when the line is under pressure, the check valve closes for normal operation. When there is no pressure in the line, the water drains out automatically through the valve.

Manual and automatic methods may work for contractors in warmer states that typically have milder winters and no hard freezes, but not those who work in the Snowbelt.

The best way to ensure that all water has been removed from low area pipes is to blow them out with compressed air.

“People will rely on check valves to a great degree, but it’s kind of a diet version,” said Madewell. “Compressed air is the most efficient method of winterizing, because it completely evacuates everything— no questions asked.”

For blow outs of any main line of two inches or less, use an air compressor with a cubic foot per minute (CFM) rating of 80 to 100. Compressors large enough to get the job done can be rented at equipment rental yards. A small shop compressor will not have the proper amount of pressure and volume to winterize the system. They may be able to produce the correct amount of psi, but only for a few moments.

“The number-one thing when dealing with winterization is the volume of air that the contractor needs to be putting through the piping to displace the water,” said Eggleston.

Calculate the exact amount of air volume needed before starting. It will vary based on the type of system, the size of the main line, and the number of sprinkler heads. Use between 40 to 80 psi of pressure, depending on the system. The bigger the system, the higher the psi number.

If you do not calculate the precise amount, air might simply travel over the water, instead of forcing it out. Or, in cases where an excess amount of air is used, you risk blowing out sprinkler heads and damaging pipes, joints, valves and drip components. Remember, rapidly moving compressed air in a condensed space can cause friction. Stop the air flow immediately once the heads have stopped draining water.

As with all professional jobs, make sure you have the proper safety gear. Eye protection is important in this pressurized procedure. There is a high likelihood of serious eye injuries from flying debris. Do not leave the air compressor unattended, or stand over system parts while the machine is operating.

Make sure all valves are open before starting the blow out. On larger properties, such as a commercial site, there may be multiple zones. Never use a compressor on an irrigation system without at least one open valve.

Insert the compressor’s air hose into the sprinkler’s blow-out valve and gradually introduce air into the system. Regulate the air flow until each zone is dry. When only a fine mist or air begins to exit the sprinkler heads, turn off the compressor.

Each zone should take approximately two minutes to dry. Rather than using one long cycle per zone, it is better to use a few shorter cycles of compressed air.

At the end of the process, eliminate any future headaches by labeling the date of the winterization with a tag.

The whole process is easy enough, but there are some majors “don’ts” to avoid. When blowing out a system with PVC piping, do not allow the air pressure to exceed 80 psi. When working with systems that have polyethylene piping, do not let the pressure exceed 50 psi. Make sure you regulate the blow out pressure, and you will be successful.


Pricing for winterization varies based on region, contractor and irrigation system.

Eric Zima with New England Irrigation finds that the licensing laws in the Northeast influence winterization prices. He can see a big variation in pricing between the states that have licensing laws in place and those that do not.

“It’s all over the place,” he said.

“I’ve seen it where sometimes it’s incredibly high and the guy is just making beer money.”

Zima is a firm believer that if contractors provide a great service and take care of their customers, they should be able to charge a fair price without complaints.

A popular way to determine a feasible price is to base the fee on the number of zones.

Take the initiative. Let your customers know the exact services you offer, and when. Explain to them the importance of taking precautions to save money in the future.

Just like that, you will have saved the day. Your clients will be able to enjoy their winter curled up by the fire. And you will know that you have provided a much-needed service.

Educating your client base about the importance of properly shutting down an irrigation system is a winwin-win situation. If you promote proactive services, you, the customer, and their irrigation system win, and nobody gets left out in the cold!