How to Winterize Sprinkler Systems?

To keep your irrigation system running, you need to winterize the sprinkler system. The process can be hectic if it’s your first time. You may require some professional consultation to know your system parts were located and how to drain the winter’s sprinkler system.

The process involves three main techniques that are blow-out, manual, and automatic drain. Blow out involves applying air pressure to drain the pipes. The automated method drains water when pressure falls, but manual empties water when valves open.  When installing your system, it’s wise to understand the cold zone you’re.

Winterizing Sprinkler System: What to do

First, it’s better to check your manual to avoid any mistakes and mess up your warranty. If unable to find it, follow the tips explained below. It’s wise to understand your cold zone, too, especially when installing the parts to ensure you use the required depth. The following methods are involved;

Blow -out

In all the three methods, you need to shut off the water supply before any operation. Blowing involves the use of an air compressor to expel any water.

Shut Off Water Supply

Switch off the water supply at the master valve to prevent more water from flowing.

How to Winterize a Sprinkler System with a Backflow Preventer

You start the blowing process by closing the backflow preventer valve and then removing the fixed plug into the port’s side. Later use, quick connect blow-out plug to secure the air compressor hose. Determine how much air your system can handle in gallons per minute(GPM) of each sprinkler head. Later divide the total GPM of each zone by 7.5  to get the cubic feet per minute you need to blow.

Open the zone in the system that is furthest from the compressor to expel water out. When the sprinkler head pops up, please turn off the compressor to prevent damage to the system, because it means the zone is empty. Compressed air through dry pipes can cause friction, create heat, and later damage.  Repeat this procedure in each site at a time.

Activate Furthest Station

Activate the station on the controller away from the compressor or sprinklers at the compressor’s highest elevation.

Close Backflow Isolation Valve

Close backflow valves and open the compressor valve to allow air to fill the system. The blow out pressure should be below the maximum operating pressure; for example, in PVC, it should not exceed 80 PSI.

Activate Other Stations

You should start operating on the furthest zone from the compressor and keep activating others each at a time.  Ensure the water in each station drains for the sprinkler head for around 2-3 minutes. As soon as the station is dry, stop blowing to prevent damaging the pipes. While running air through each station, make sure at least one valve is open.

Shut Off the Compressor

When the system dries, disconnect the compressor. Open the valves on the channel to release excess air and prevent damage.

How to Winterize Sprinkler System Without Air Compressor

It done through two processes;

  • Manual
  • Automatic

Manual Drain

Open the manual drain valves located at the end and low points of your sprinkler system. After opening the valve, the water drains freely.

Drain Remaining Water

Open either the boiler drains or drain cap on the stop and waste valve. Open all the best cocks on the backflow device and drain all excess water.

Pull on the Sprinklers

Pull-on sprinklers so that water can drain out of the bottom of the sprinkler head.

Watch Out Excess Water

When valves are not in a good position, some water can remain on the backflow, piping, or sprinklers. In case of such a situation, dry out the remaining water.

Close the Manual Valves

When you finish draining water, close all opened drain valves.

Automatic Drain

The method applies when automatic drain valves are at the endpoints and low points of your system. Valves open and drains water once the pressure in the pipes is less than 10 PSI. It’s wise to prompt the pressure to drop before valves unlock.

  • Activate a station. Turn on one of the sprinkler heads along the mainline to help relieve pressure.
  • Drain excess water between the shut-off valve and backflow device.
  • Pull up on sprinkler valves to get water out of the bottom.

Insulate Your System

Suppose your system is above the ground like the valves, it’s best to insulate exposed parts. You can use a foam insulating tape, foam pipe covers, and more. Follow the instructions from the package cover to cover exposed pipes and other components. Insulation helps against freezing, cracking, and blockage of drainage pipes.

Winterizing Sprinkler System Cost

The cost of winterizing depends on the zone you are in and the irrigation system. For instance, in region eight or less, you can pay $125-150 to a professional company. It can be more costly when doing it yourself due to the equipment’s renting fee like an air compressor. If you need to purchase, the tools will cost you between $ 200-300.

When Should I Winterize My Sprinkler System?

The best moment to winterize your system is between October 1st – December 15th. It’s best to winterize some days before cold temperatures to prevent damage.

Why is it Necessary to Winterize a Sprinkler System?

When you don’t winterize your system, you run the risk that water will freeze in the valves, pipes, and sprinkler heads. Freezing causes the water to expand, making your system’s parts burst and destroy your whole system.

Check this too: Best Impact Sprinkler for Low Water Pressure

How Deep Should Sprinkler Pipes be Buried?

The standard pipe depth is between 8-12 inches. The deepness allows easy installation of sprinklers and other parts. Depending on the pipes’ size, you may need to add an inch or more depth. For instance, if you dig 10 inches for a 2-inch tube, you’ll require 12 inches of depth. 10-12 inches depth protects your lines from any damage and freezing in the cold zones.

How Do You Turn Water Back on After Winter?

  • Find your systems main shut off valve in the basement or other places.
  • Find also the vacuum breaker. Close the vacuum breaker test valves, ensuring each slot is perpendicular to the stem.
  • Open the vacuum breakers shut off valves so that they are parallel to the pipes.
  • Reinstall the main valve bleeder cap.
  • Later, open the main valve slowly to avoid a water hammer that can damage the system.
  • Test your system each zone at a time. Additionally, recheck the breaker and valves for any leaks
  • or other issues and fix them.


If you live in the cold zones, you will require to learn how to winterize your system. You should also find out the materials of your piping to avoid issues with the compressor. Second, you should keep in mind the PSI of your pipes and don’t leave the compressor unattended.

If you cannot winterize yourself, consult a professional company. Again, make sure your system is from the best brands like the hunter sprinkler system and rain bird sprinkler.