How to Winterize Your Irrigation System Before the First Freeze (5-Step Checklist)

Late October is a good time to put irrigation winterization on your Westchester County checklist. The goal is simple: shut down the system before freezing weather can leave water trapped in pipes, valves, or exposed equipment. A little planning now can help prevent cracked components and an unwelcome repair in spring.

The right timing depends on the weather and your property. Don’t wait for a hard freeze to arrive: arrange winterization while there is still time to complete it. If you’re already reviewing other seasonal work, our fall landscape checklist is a useful companion.

Here’s a practical five-step guide to what winterization involves, and where professional help matters.

1. SHUT OFF THE IRRIGATION WATER SUPPLY

Locate the dedicated shutoff for the irrigation system and turn off its water supply. This is different from simply switching the controller off: a timer set to “off” does not stop water from reaching the system.

If you’re not sure which valve controls irrigation, don’t guess. Some properties have more than one shutoff, and the setup can vary. Ask an irrigation professional to identify the right valve before operating it.

Once the supply is off, keep the system from starting on its regular schedule while winter work is underway. That helps avoid an unexpected cycle when a line is being drained or serviced.

A helpful first check: Make a note of where the shutoff is, which areas each zone waters, and whether any exposed pipes or equipment need attention.

2. DRAIN LINES AND COMPONENTS DESIGNED TO DRAIN

After the supply is shut off, the system needs to be cleared of water as appropriate for its design. Some irrigation systems have manual drain valves or other features intended to release water from certain sections. Follow the instructions for your specific system; don’t assume that opening one drain empties every line, valve, or sprinkler head.

Gravity draining may leave water behind in low points or components. That’s why a system that appears empty may still need a professional blowout. The Colorado State University Extension winter preparation guide explains why the right winterization method depends on the system and its components.

If you don’t know what type of drain your system has, or which parts it reaches, pause here rather than opening unfamiliar valves. A careful inspection can prevent a small seasonal task from turning into a damaged fitting.

3. BLOW OUT THE ZONES WITH COMPRESSED AIR, CAREFULLY

For most in-ground systems, winterization includes clearing the irrigation lines zone by zone with compressed air. This is often called a blowout. Each zone is handled individually so remaining water can be pushed out of the pipes and sprinkler heads.

This is where professional equipment makes a visible difference. A proper blowout calls for a large, tow-behind commercial air compressor rather than a small portable unit. These compressors deliver the high volume of air, measured in cubic feet per minute, needed to push water out of long lateral lines and up through every head, which a small compressor struggles to move. Pressure is still regulated carefully; volume does the work, not force.

The air line connects at the backflow preventer on the side of the house. That assembly is the standard connection point for a blowout: the professional positions the isolation valves correctly, attaches the air line at the appropriate fitting, and sends air into the system from there. Because the backflow preventer protects the household water supply, its valves are handled deliberately rather than forced, and the assembly is drained and set for winter afterward.

Do you know where your backflow preventer is, how its valves should sit before the air line goes on, and how much air your system’s lines and heads can take? Those are exactly the details a trained technician works through on every property. Hunter’s winterizing guide also outlines the equipment and safety considerations involved.

A good blowout is controlled and methodical, zone by zone, not a matter of forcing air through the whole system at once. It’s one of those seasonal tasks where the right compressor and a practiced hand make a real difference.

4. PROTECT THE BACKFLOW PREVENTER

The backflow preventer is an important part of an irrigation system, and many properties have it exposed above ground. Because it can hold water, it needs winter protection suited to its model and installation.

After the lines are winterized, the backflow assembly may need to be drained or placed in a winter position according to its manufacturer’s instructions. Insulating it with an appropriate cover can help protect it from cold weather, but insulation alone may not be enough if water remains inside. Avoid tightly wrapping components in a way that traps moisture, and don’t assume every assembly is handled the same way.

If you can’t identify the device or its instructions, ask a professional to check it. A mistaken connection or valve position can cause damage, and backflow protection should not be bypassed or altered casually.

5. UPDATE THE CONTROLLER AND CONFIRM THE SHUTDOWN

Once winterization is complete, check the irrigation controller or timer. Set it to “off,” “rain,” or the manufacturer’s recommended winter setting so it won’t run on its normal schedule. The exact setting varies by controller, so consult its manual if you’re unsure.

You may not need to disconnect the controller or remove its backup battery. Some models retain programming or clock settings with a battery, while others have different instructions. Follow the guidance for your unit and keep the controller protected from the elements.

Before wrapping up, confirm that the water supply remains off and that every zone has been addressed. Make a note of anything that needs attention in spring, such as a damaged head or a controller setting you’ll want to restore.

WHY A DIY BLOWOUT CAN LEAD TO CRACKED PIPES

A blowout can look straightforward: attach a hose, run a zone, and wait for water to stop. But a system is made up of connected parts with different pressure limits and places where water can collect. Without proper equipment and a clear understanding of the layout, it’s easy to apply too much pressure, miss a zone, or damage a backflow device.

That’s why a professional winterization is more than a quick burst of air. It’s a deliberate shutdown, with attention to the water supply, each zone, exposed equipment, and the controller. If your property has an unfamiliar layout, multiple irrigation areas, or a backflow assembly you can’t identify, professional help is a sensible choice.

A WINTER-READY SYSTEM, A BETTER SPRING

Winterizing your irrigation system protects more than pipes. It helps preserve the quiet infrastructure that supports a healthy lawn and thoughtfully cared-for plantings. For the broader role irrigation plays in a landscape, read our article on irrigation systems and how they keep your lawn and plants healthy.

Sound Shore Landscaping provides seasonal irrigation services, including winterizations, for residential and commercial properties. If you’d like a hand preparing your system before freezing weather, explore our irrigation and landscape services or visit our service areas page to start a conversation.

Prepare for winter. Welcome spring with confidence.