WHEN I LIVED IN upstate New York, I hated winter and everything that went along with it. Having to protect my body from the freezing cold with boots, gloves and heavy sweaters put a strain on my already tight budget. However, the one thing I never had to worry about protecting was my sprinklers, because I was fortunate to have an excellent landscape contractor who would visit my home every year and winterize my irrigation system.

Unlike a new pair of boots, paying for this service wasn’t a luxury, it was a necessity. Water expands when it freezes, and if the irrigation system isn’t well drained, the expanding water will turn to ice and crack the PVC pipes. Even polyethylene, which is more flexible, will rupture under the pressure exerted by the expansion of frozen water. This is why, in certain parts of the country, contractors unload their lawn mowers from their trucks and replace them with air compressors as soon as the weather turns cooler.

Like all regions of the country where the frost level extends below the depth of the irrigation piping, the ritual of irrigation winterization is a top priority. “There are two basic methods of water removal,” says Troy Leezy, CID, CWCM-L, CLIA, and marketing manager for Hunter Industries, San Marcos, California. “Manually drain the system, or blow out the system using an air compressor.”

Manual draining was very popular in the ‘70s, and is still in use today where irrigation lines have been graded to common points at the lowest areas on the property. “To drain these systems manually, you simply shut off the irrigation water supply and open all the manual drain valves,” Leezy says.

“When all the water has drained out, close all the manual drain valves, and you’re done.”

To start the “blow out” process, shut off the irrigation water supply and, with the compressor valve in the closed position, attach the air compressor hose to the fitting. Activate the station on the controller with the zone or sprinklers highest in elevation and the furthest from the compressor. Close the backflow isolation valves. Then slowly open the valve on the compressor; this should gradually introduce air into the irrigation system. The blow-out pressure should remain below the maximum operating pressure specification of the lowest pressure-rated component on that zone.

“The big benefit in blowing out an irrigation system is that it’s a faster and more accurate method to make certain that each pipe is totally clear. After you hook up the compressor and turn it on, you can visually watch the heads pop up on each sprinkler nozzle,” says John W. Reffel III, LEED AP, CLT, of JLS Landscape & Sprinkler, Sedalia, Colorado. “Once the discharge goes from water to air, you simply disconnect the compressor and go onto the next job.”

For commercial systems with multiple zones, each zone should be activated until no water can be seen exiting the heads; this should take approximately two minutes or more per zone, says Leezy. “Once the zone is dry, you should not continue to blow air through the pipe. Compressed air moving through dry pipes can cause friction, which will create heat, and the heat could cause damage,” he says.

Another caution when using an air compressor is to be sure that you’re not putting too much pressure on the sprinkler heads. “Some compressors will get upwards of 250psi, and that can be too much on some types of pipes or fittings; you’ll run the risk of nozzles popping off like champagne corks,” says Reffel, “It’s always a good idea to bring along a ladder, in case you have to retrieve the heads from the gutters of the house.”

...it’s difficult to sell a winterization service when Mother Nature decides to bring unseasonably warm weather.... If people wait until the last minute to winterize, they run the risk of having some above-ground pipes freeze...

“The compressor size really depends on the system size. Usually, bigger is better and faster. While a smaller compressor will work, it might take longer to get the job done,” says Jeff Trost, president, Trost Irrigation Companies, headquartered in Orion, Michigan. “The average residential system should take about 30 to 45 minutes, but again, this all depends on the compressor size and the irrigation system size. We can do a proper residential winterization in under a half hour for a small residence. Unless there is a problem, we can usually take care of about twenty clients a day.”

Trost says the biggest problem is that, while people know the freezing temperatures are on their way, it’s difficult to sell a winterization service when Mother Nature decides to bring unseasonably warm weather to areas of the country that are expecting frost. “If people wait until the last minute to winterize, they run the risk of having some above-ground pipes freeze, which means we now have to thaw them before we can winterize the rest of the system. It’s not a big deal, but it is very time consuming, because we have to use a handheld dryer or heat blow gun before we can hook up the compressor. So, we always tell our clients, no matter what the thermometer reads, it’s best to start early.”

No matter the size of the irrigation system, the one component they all have in common is the backflow preventer. Irrigation pipes can certainly be a problem to repair if they fracture. However, they are underground and are somewhat better protected from freezing than the components that are above ground, especially those on a backflow prevention device.

“We do winterization for bigger systems in municipalities, but we also do some residential,” says Chris Willis of Colorado Total Maintenance, Denver, Colorado. “Out here, every house has an above-ground backflow device, so we make sure that those are drained first. Then we go back and start draining the main line and blowing out the system.”

Paul Wait, product manager at Wilkins, a Zurn company in Erie, Pennsylvania, adds, “If there is any water left in the pipes, the amount is so small that it really doesn’t pose any big threat of damage to the pipes if it freezes. However, you also need to make certain that someone doesn’t turn the main water valve back on by mistake.”

The best way to avoid that from happening, says Wait, is for the contractor to put some kind of label on that particular valve, warning people not to turn the water on. “If someone should accidently turn on the water and it freezes, the contractor is going to be libel for any damaged components in the system, since it will be very hard to determine how that valve was turned back on. As an extra precaution, I recommend attaching a bright red or fluorescent yellow tag to the valve, warning people to stay away.”

Another way to avoid possible mistakes and future liability is to have an excellent customer service program in place. Trost offers his clients a “preferred customer plan,” a complete service contract that includes spring turn-on, a mid-summer check and fall winter ization.

As an incentive, he also offers discounted rates for other services throughout the year to those clients who sign up for the program.

With winter and cold weather pretty much a sure thing, you would think that irrigation winterization services would be the one area contractors could count on for a steady revenue stream, even in difficult economic times. Unfortunately, just the opposite is true, as Scott Silverman, president, The Automatic Group in Hempstead, New York, explains.

“What we’re seeing with the current economic climate are the price wars. People who have been laid off think that all they need to do is buy an air compressor and they can do winterizing at a discount. They’ll do winterizations but they won’t guarantee the work, should something break in the system.”

“The way we combat the discounters is that we guarantee everything—from the beginning of the winterization process to when we open the system in the spring. If there is any freeze damage, we’ll fix it for free, and since the competition can’t offer that kind of guarantee, we’re able to keep our clients.”

Trost agrees. “With the dip in the economy, we’ve seen many people who have lost their jobs deciding to go into this business. It has become very competitive, but we can show our customers that we’ve been in business a long time. We point out that these guys who just took this on might not have as much experience in winterizing and may be out of business come the spring. Then what is the property owner going to do if something goes wrong?” Another potential opportunity for irrigation winterization is the homes that have been abandoned or have gone into foreclosure. “Our business has certainly increased, with the number of calls we’re getting from the city,” Trost said. “We’ve been called out on a number of properties where they didn’t winterize and the water just kept shooting up the side and freezing, creating an iceberg with continuing water flow.”

“Some people in foreclosure have just walked out, leaving the house empty. They don’t bother paying for any winterizing on their irrigation systems, so we’ll get a phone call from the city to come out and turn the water off. It’s a sad situation, but the service has to be done.”

Silverman adds, “We also have contracts with our ‘snow birds’—homeowners who need to turn off their irrigation systems before they pack up and head for Florida. They know that we’re on a regular schedule, and that everything will be turned on and working perfectly when they return in the spring.”

Unless they, like myself, decide that they’ve had enough of the cold and move to sunny California, where the only protection needed is a good sunscreen!