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With the long cold winter ahead, winterizing the irrigation systems you manage is extremely important to the health of your business. Preparation is vital for your pipes to endure the bitter weather and be ready to work properly once spring rolls around again. Whether you live in a temperate climate or you will be digging yourselves out of the white stuff for 5 months, different approaches to winterizing are necessary.
1. Turn off the water to the irrigation system at main valve. The main shut off valve for your irrigation system needs to be ?EUR??,,????'?????< 2. If you have an automatic irrigation controller, set it to the ?EUR??,,????'?????< Setting the system to ?EUR??,,????'?????< 3. Turn on each of the valves to release pressure in the pipes. This important step prevents the build up of air pressure from damaging pipes, which can be as destructive as leftover water that freezes and expands. 4. Drain all of the water out of any irrigation components that might freeze. There are three common types of water removal. They are manual drain, auto drain, and blowout.
When manual valves are located at the end and low points of the irrigation piping, simply shut off the irrigation water supply and open all the manual drain valves. Once the water has drained out of the mainline, open the boiler drain valve or the drain cap and drain all the remaining water that is between the irrigation water shut off valve and the backflow device. Then, open the test cocks on the backflow device.
When you have pulled up on the sprinklers to allow the water to drain out the bottom of the sprinkler body, close all the manual drain valves.
Automatic drain valves will, by design, open and drain water if the pressure in the piping is less than 10 PSI. Shut off the irrigation water supply and activate a station to relieve the system pressure. Once the water has drained out of the mainline, open the boiler drain valve or the drain cap and empty the remaining water that is between the irrigation water shut off valve and the backflow device. Then, open the test cocks on the backflow device. In some areas you might have a combination of the manual drain system on the mainline and auto drain system on the lateral lines.
The blow out method utilizes an air compressor attached to the mainline via a quick coupler, hose bib or other type connection. Shut off the irrigation water supply and, with the compressor valve in the closed position, attach the air compressor hose to the fitting.
Close the backflow isolation valves, and then slowly open the valve on the compressor. Never exceeding 80 PSI, the blow out pressure should start out low and gradually increase.
Start from the furthest station from the compressor, and work your way back. Take approximately two minutes or more per station, and stop when no water can be seen exiting the heads, since compressed air moving through dry pipes can cause friction, heat, and damage. Once the water has been removed from the irrigation system, disconnect the air compressor and release any air pressure that may be present.
80: Psi, the maximum pressure rate needed for blowing out an irrigation system during the winterization process. Although many air compressors can charge over 120 psi, 60 psi is considered ideal for winterization.
30 to 45: Minutes, the average time it takes to winterize a typical residential irrigation system. Source: John Deere Landscapes
Francisco Uviña, University of New Mexico
Hardscape Oasis in Litchfield Park
Ash Nochian, Ph.D. Landscape Architect
November 12th, 2025
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