Why September is the right month
Most NoCo homeowners don't think about sprinklers until the first hard freeze in October — and that's exactly the problem. By mid-October, every irrigation crew in Loveland, Berthoud, Johnstown, Fort Collins, Greeley, Windsor, and the surrounding towns is booked solid. If you wait until you see frost on the windshield to call, you're either paying a rush fee or going on a waiting list.
September is the calm window. The lawn still needs water, the weather is easy to work in, and a 30-minute walk-through now saves you both a frozen backflow in November and a second trip charge later.
The 5 tasks (in order)
- Run each zone manually for 2–3 minutes. Use the manual setting on the controller — don't rely on the schedule. You're looking for water at every head and steady pressure across the zone.
- Walk the yard while each zone runs. Flag anything wet when it shouldn't be: soggy spots at the base of a head, water bubbling up from a fitting, a stream shooting straight up, or a head that doesn't pop up at all.
- Adjust coverage. Late-summer grass growth and edging often leaves heads spraying the sidewalk, fence, or driveway. A simple turn of the screw on top of the head fixes most of it — no parts needed.
- Note repairs in writing. Sunken heads, a sticky solenoid valve, a cracked poly fitting, or a missing backflow cover are all small enough to bundle into the same visit as the blowout. The crew can price it once and fix it in one trip.
- Book the October blowout now. Pick a date 2–3 weeks before your town's average first hard freeze. Calling in September locks your slot and last winter's rate.
What to look for during the walk-through
- Sunken heads — grass grows over a head that's settled below grade, and you end up with a dry patch in the middle of a zone.
- Tilted heads — usually from a tire or a rake. A tilted head waters the sidewalk instead of the lawn.
- Leaking valve boxes — if a valve box stays wet between cycles, the solenoid or diaphragm is starting to go.
- Cracked poly at the fitting — a small stream of water when the zone is off is almost always a cracked compression fitting.
- Backflow device exposed — NoCo winters can drop the brass body of a backflow below freezing. If your front is above grade and uncovered, add an insulation cover at the same visit as the blowout.
What still needs to run in September
Don't shut the system down early. Cool September nights and warm days mean cool-season grass — bluegrass, fescue — is rebuilding roots. Aim for roughly 1.0 to 1.25 inches of water per week from rain plus irrigation. As nights drop into the 40s, cut back one watering day per week. After your town's first hard freeze, stop running scheduled cycles entirely.
If you're not sure what your lawn actually needs in September versus October, the right move is to walk it with someone who'll be honest about it — and who can do the fix at the same visit as the blowout.
What the October blowout actually does
A proper winterization pushes compressed air through each zone to clear the lines, then drains the backflow preventer and leaves the test cocks cracked. A high-CFM, regulated rig clears the lines in a few seconds per zone without exceeding the pressure rating of poly (typically 80 psi). A home compressor usually doesn't push enough CFM to fully clear the lines, and too much pressure splits fittings or pops valve solenoids — which is the opposite of what you wanted to prevent.
The full guide to NoCo winterization — frost dates by town, what to skip, and what to bundle — is in our sprinkler winterization post.
When to call a pro in September
- You ran the zones and found more than one or two small issues.
- Coverage is uneven — some areas soaked, others dry — and adjusting heads doesn't fix it.
- You want one fall visit that handles the walk-through, the small repairs, and the October blowout as a package.
- You're already booking snow removal and want a single crew to handle both.
Want us to walk the system and bundle the blowout?
Call (970) 685-9512 or use our quick quote form. We'll walk each zone, flag the small repairs, and lock your October blowout slot — usually in the same trip.
Serving Northern Colorado: Berthoud, Johnstown, Loveland, Fort Collins, Windsor, Greeley, Milliken, Timnath, Severance, Mead, Longmont, Evans, Firestone, Frederick, Eaton, and Ault.