When to Winterize Your Sprinklers in Erie, CO (And What Happens If You Wait)

In Northern Colorado, you should winterize your sprinkler system between late September and mid-October, before the first hard freeze. Winterization means blowing compressed air through every zone to clear water from pipes, valves, and backflow preventers. Skipping it risks cracked pipes and split valves, with repair bills typically running $500-$1,500.

Winterizing is the single most important maintenance task of the year. Get it right and your system wakes up fine in spring. Skip it and you're writing a big check.

When to Schedule Your Blowout

In Northern Colorado, the window is late September through October. We start booking winterizations in September and October fills up fast. By mid-October, we're usually booked solid.

The first hard freeze (below 28 degrees for several hours) can happen anytime from mid-October on. In 2024, Erie saw its first hard freeze on October 18th. Some years it holds off until November. You can't predict it, so don't gamble.

Our advice: book your blowout for October. If you wait until the weather forecast shows a freeze coming, every irrigation company in Weld County is already slammed.

Why a Shop Compressor Won't Work

Every year someone tells us they'll just do it themselves with their garage compressor. Here's the problem: a typical shop compressor puts out 2-5 CFM (cubic feet per minute) of air. To properly blow out a residential sprinkler system, you need 80+ CFM from a commercial-grade compressor.

That's not a small difference. That's like trying to fill a swimming pool with a garden hose versus a fire hydrant.

With a shop compressor, you'll push some water out, but a lot stays behind in the lateral lines and fittings. That trapped water freezes, expands, and cracks PVC pipe or splits poly tubing. You won't know until spring when you turn the system on and water starts gushing from underground.

We use truck-mounted compressors rated at 185 CFM. Each zone gets hit with enough air volume to clear it in 1-2 minutes. That's what it takes to do it right.

What a Professional Blowout Costs

A standard residential blowout runs $75-$125 depending on the number of zones. Most systems in Erie and Longmont have 5-8 zones and take about 30-45 minutes.

Compare that to $500-$1,500 in freeze damage repairs. It's the best $100 you'll spend all year.

What About Those Warm November Days?

This catches people every year. It's November 10th, it's 62 degrees outside, and they're thinking maybe they should turn the system back on for one more watering. Their lawn looks a little dry.

Don't do it.

Your lawn is going dormant. It doesn't need the water. And even though it's warm today, the overnight lows are dipping into the 20s and 30s. If you run your system and water is sitting in the pipes when it drops below freezing at 3am, you're right back to cracked pipes.

Once we blow out your system, leave it off until spring. Period. If you're worried about new sod or fresh seed, hand-water those spots with a hose.

What Happens During a Proper Blowout

Here's what we do when we show up:

• Shut off the main water supply to the irrigation system at the backflow preventer
• Open the manual drain if your system has one
• Connect our compressor to the blowout port
• Work through each zone one at a time, running air until each head blows clear (no more water mist)
• Open the backflow test cocks so water doesn't sit in the preventer and crack it
• Set the controller to rain mode or off so it doesn't try to run empty zones

The whole thing takes 30-45 minutes for a typical home. We'll also flag anything we notice: heads that look damaged, areas where we suspect a leak, or controller issues. That way you know what to address in the spring.

The Short Version

• Book your blowout in September or early October
• Don't try it with a shop compressor. You need 80+ CFM.
• Professional blowouts cost $75-$125. Freeze damage costs $500-$1,500.
• Once it's blown out, leave it off. Even if November feels like summer.

Trailhead Lawn & Irrigation handles winterizations across Erie, Longmont, Louisville, Lafayette, and surrounding areas. We book up fast, so don't wait. Call us or schedule online to lock in your spot.