How Do You Winterize an Irrigation System in Western Colorado?

Shut the water off, get every drop out of the lines, and protect anything that holds water where it can freeze. In Western Colorado that means draining or blowing out sprinkler and drip lines, opening valves so they can't trap water, and clearing yard hydrants before the first hard freeze settles into the valley.

The tricky part out here isn't the cold. It's the swing. A late-October afternoon in Hotchkiss can run shirtsleeve warm and drop well below freezing by midnight, and that cycle is what cracks fittings, splits valve bodies, and heaves pipe sitting full of water. The work starts once the ditch companies shut down and overnight lows settle in below freezing, usually sometime in October around here. If you're still deciding whether the season is over, we covered that in an earlier post on knowing when it's time to shut down your irrigation for the season.

What Is an Irrigation Blowout, and Do You Need One?

A blowout pushes compressed air through the system to force out water gravity can't reach. You need one on just about any pressurized sprinkler or drip system around here, because almost nothing in this country is laid out dead flat. There's always a low spot, a long lateral, or a head holding water in the body.

Work it one zone at a time, water off and the zone valve open, until the mist stops and only air comes out. Air sent through everything at once takes the path of least resistance and leaves the rest full.

One caution worth taking seriously: keep the air pressure inside what your components are rated for. That number comes off the manufacturer's spec for your heads, valves, and pipe, not off a guess at the gauge on a borrowed compressor. Too much air does more damage in a minute than a winter of neglect.

What a thorough blowout should reach:

• Zone valves and the manifold
• Sprinkler laterals and every head on the zone
• Drip submains and the far end of each lateral
• The backflow assembly, per that device's instructions
• Any line running to a stock tank, garden, or outbuilding

How Do You Drain Sprinkler Lines Without a Compressor?

You can drain a system by hand if it was built to drain: shut off the supply, then open every low-point drain, manual valve, and end cap so water runs out instead of standing. A system with drain valves at the low spots and lines pitched toward them empties most of the way on its own.

The catch is that gravity only gets what gravity can reach. Sprinkler heads, check valves, filter housings, and any flat or back-pitched run stay full, and those are the parts that split. If you don't know how your system was laid out, air is the only way to be certain. CSU Extension's fact sheet on preparing a sprinkler system for winter walks through both approaches.

How Do You Winterize a Yard Hydrant?

A frost-free yard hydrant is built to winterize itself: close the handle and the valve at the bottom of the standpipe shuts, letting the water above it drain out below the frost line instead of sitting where it can freeze. Your fall job is confirming it actually does that.

The number one reason a frost-free hydrant freezes is a hose left attached, which can keep the standpipe from draining and leave water sitting in that pipe all winter. Pull every hose before freeze-up, and leave the handle all the way down rather than cracked open.

Run each hydrant in the fall and listen for it to drain after you shut it. If it doesn't, the drain port is plugged or the ground has stayed saturated. That's a dig-and-fix job better done in October than February. Hydrant parts are brand-specific, so bring the make and model to the counter in Hotchkiss or Olathe; we carry Woodford hydrants and the components that go with them.

What Else Freezes That People Forget?

The parts that get missed sit above ground and out of mind. Anything with a housing that holds a cup of water will crack, and most cost more than the pipe does.

• Backflow assemblies: winterize per the device's own instructions
• Filters and screens on a drip system: pull the element, drain the housing, leave it open
• Pressure regulators and gauges
• Pumps and pressure tanks in unheated well houses
• Hose bibs, quick couplers, and the hoses
• Fertilizer and chemical injectors

If You Irrigate Off the Ditch

Ditch-fed systems carry one extra problem into winter: sediment. Water out of a Western Colorado ditch hauls sand and silt all season, and whatever settled in a filter housing, a sand separator, or the bottom of a drip submain freezes into a plug that's hard on the housing and harder to clear in spring.

Flush filters and separators before draining them, pull screens and disc stacks and store them dry, and move sediment out of the low end of drip submains while you still have water to do it with. Growers running Netafim or Rivulis drip, Nelson sprinklers, or Amiad filtration should check each manufacturer's off-season guidance. The steps aren't identical across brands. Gated pipe gets drained and stacked where it won't be crushed.

Common Questions

When should you winterize an irrigation system in Western Colorado?

Once your ditch company has shut water off for the season and overnight temperatures stay below freezing. That's generally October in the North Fork Valley, Olathe, and Delta, and earlier at higher elevation. Going early costs nothing. Going late costs fittings, valves, and heads you won't find broken until spring startup.

Can you winterize a sprinkler system without an air compressor?

You can if the system was built to gravity-drain, with manual drain valves at every low point and lines pitched toward them. Hand-draining won't clear sprinkler heads, check valves, or flat runs. On most systems in this country, compressed air is the only way to be confident the lines are empty.

Will a frost-free yard hydrant freeze?

Yes, if it can't drain. A frost-free hydrant empties its standpipe below the frost line each time you shut it, but a hose left attached, a plugged drain port, or saturated ground that won't take the water leaves that pipe full. Pull hoses in fall and confirm each hydrant drains after shutoff.

Do you need to winterize drip irrigation lines?

Yes. Drip emitters, submains, and filter housings all hold water, and freeze-thaw splits emitters and cracks fittings over a Western Colorado winter. Flush the lines, drain or blow out the submains and laterals, and pull filter elements so housings sit empty. Follow your drip manufacturer's off-season instructions for tape and tubing.

Get It Drained Before the Cold Sets In

Winterizing isn't complicated, but it's unforgiving: the mistakes stay hidden until April, when the line nobody drained comes apart the first time it sees pressure. If you need hydrants, drain valves, filters, or fittings before freeze-up, we keep them on the shelf at both counters alongside the rest of the irrigation and water supply lines we carry. Send us your plans and we'll put together an accurate materials list.