How to Winterize Your Sprinkler System

Protect pipes and valves from damaging freezes and thaws.

Your sprinkler system isn’t just a tool to keep your lawn hydrated, it’s an investment worth protecting. If temps in your area ever drop to 32 degrees fahrenheit or below, you risk damaging the pipes and valves if your system isn’t ready. Any water left in it over winter will freeze and thaw—expanding and contracting—causing warps, cracks, and breaks. It’s important to remove all water from your sprinkler system to avoid expensive repairs or replacement in the spring.

When should I get my sprinkler ready for winter? When leaves start falling, it’s time to think about winterizing your sprinkler system. Watch the weather forecasts because you want to beat the first frost by at least a week. And, come spring, don’t start your sprinkler too early. You don’t want to be surprised by a late frost, plus, early in the season, natural rainfall may be enough to keep your lawn happy.

How long will it take to winterize my sprinkler system? This little outdoor project—likely one of your last for the season—may take anywhere from 30 minutes to 3 hours, depending on the size, design, and setup of your system.

Think Safety First

  • Wear safety goggles — Regardless of which draining method your system requires, all of them are pressurized, so protect your eyes by putting on safety goggles before you get to work.
  • Keep a safe distance — Water or air may come through the sprinkler heads at high pressure, so don’t stand close to them during this process.
  • Wear hearing protection — If your system requires use of an air compressor, it’s smart to protect your ears while you’re running it.
  • Protect kids and pets — Keep them inside during this process to shield them from noise and injury.

Prepare your sprinkler system for winter

1. Inspect your system

Check for damaged or missing spray heads and look for leaks. If you notice any problems, get them repaired before you do anything else.

2. Turn off your water

Shut off your water supply at the main valve next to your water meter. This is not the same valve as the one supplying water to your house. If your system has backflow device valves, shut them off as well. There are typically two. Turn off both.

3. Turn off your timer

If your sprinkler system has an automatic timer, you need to either shut it off for the winter, which may clear any settings you programmed, or turn it to rain mode, which stops the signal to water, but maintains your settings for spring.

4. Drain the water

There are three ways to drain water from your sprinkler system. The right method for you depends on the type of system you have. If you’re not sure which method to use, check your sprinkler system guide.

  • Manual draining - Manual draining is the simplest method, but it still requires wearing eye protection because the water in the pipes is pressurized. With your safety goggles on, locate the valves and open them one at a time. Lift the sprinkler heads to release more water. Once you’ve drained all the water, close the valves.
  • Automatic draining - If your sprinkler system is designed for automatic draining, once you shut off the main valve, pressure will fall below a certain threshold for PSI and the water will drain automatically. In many cases, you can trigger this by turning on one of the sprinkler heads after you shut off the water supply. Most of the water will drain automatically, but you need to make sure it’s all gone. Each valve has a plastic cap with wires protruding from it. This is called a solenoid. Just loosen those caps to let air in and push out any water that’s trapped, then tighten them when the water is gone. Again, protect your eyes with safety goggles.
  • Blow-out draining - Blow-out draining involves forcing compressed air through your sprinkler system, which, in turn, forces excess water through the sprinkler heads. While the primary steps of this process are common to most sprinkler systems, consult your manual for instructions specific to your model. Wear safety goggles to protect your eyes.
  • Check your manual to make sure your system is designed to handle blow-out draining.
  • Make sure you have the right air compressor for your pipes. While the compressor needs to provide at least 40 PSI to do the job, polyethylene pipes handle pressure up to 50 PSI, and PVC pipes can withstand up to 80 PSI.
  • Connect the air compressor to your sprinkler system. If your system doesn’t have a built-in quick coupler, you may need a quick-connect hose adapter that you can screw into the blow-out port.
  • Open the blow-out port valve to let air flow toward the zone valves.
  • Blow out one zone at a time, starting with the farthest away. Blowing out too many at once might burst your pipes and fittings.
  • Keep your eye on the pressure as you do the blow-outs to make sure you stay below maximum capacity.
  • Once each sprinkler head stops emitting water, shut it off.
  • When you’re done and the air compressor is off, release any pressure that’s left in your sprinkler system by opening and closing every valve on the backflow preventer.

5. Insulate exposed parts

Once you’ve turned off the water supply to your sprinkler system, stopped your timer, and drained all the zones, you can take one more easy, inexpensive step to add extra protection - Insulation.

Cover any exposed pipes, the main shut-off valve, and backflow preventers with insulation tape, foam covers, or straw. Just be sure not to block air vents or drain outlets.

Be sure to store any other watering equipment—like hoses, watering wands, and nozzles—so they are safe during the harsh weather, too.

Please note these are general tips, please always read and follow directions and manuals specifically for your product.