The short answer
If you have an in-ground sprinkler system, it needs to be blown out every fall. In Aurora this year, plan to have it done by October 15. That's the date the city's new ordinance requires residential spray irrigation to stop, and it's already past our average first freeze.
I'm Chris, and I own No Mow Worries. Searches for "sprinkler blowout" in Colorado hit their highest point of the last three months this week, so I know a lot of you are asking the same thing. Here's the straight answer for Aurora, Centennial and Foxfield.
When do sprinklers have to be off in Aurora?
On September 28, 2026, Aurora City Council passed a water-saving ordinance with seasonal limits on spray irrigation. Per Aurora Water:
- Residential customers with lawns on a residential meter must stop irrigating by October 15.
- Spray irrigation stays prohibited from October 15 through April 30 for residential yards, parks and athletic fields.
- Multifamily and HOA areas that are not communal-use space had to stop by October 1.
Hand-watering trees and shrubs is still allowed year-round, so you can still give a young tree a drink during a dry winter stretch.
In Centennial or Foxfield? Check which utility is on your water bill. Denver Water customers had to stop all lawn watering and spray irrigation after September 30, 2026 under its Stage 1 drought rules, and Denver Water says sprinklers need to stay off into spring 2027 until its board decides otherwise.
When should I blow out my sprinklers?
Before the first hard freeze, and in Aurora, no later than October 15. The National Weather Service puts Denver's average first freeze (32 degrees) on October 7. Recent first freezes were October 18 in 2025, October 25 in 2024 and October 13 in 2023. In 2020 it came on September 8. So the average date has already passed, and there's no upside to waiting.
The part most exposed to cold is the backflow preventer, the brass assembly that sticks up out of the ground near the house. If your blowout is a few days out and a hard freeze is in the forecast, CSU Extension suggests wrapping the backflow and its pipes down to ground level with insulation, then plastic, secured with duct tape.
Isn't turning off the controller enough?
No. Turning off the controller stops the watering, but the water is still sitting in the pipes, valves and heads. CSU Extension explains that water expands by about one-eleventh when it freezes, which is enough to burst pipes, crack valves and split sprinkler cases.
CSU also doesn't recommend relying on manual or automatic drain valves. Buried pipe shifts over time and creates low spots that trap water. And systems with electric valves have to be blown out with air, because there's no other way to get the water off the top of the valve diaphragm.
Can I blow out my own sprinklers?
You can. CSU says a homeowner can do it with the right compressor, pressure regulation and know-how. Here's the short version of CSU's fact sheet 4.719:
- Shut off the water at the stop-and-waste valve. It may be in the basement, a crawlspace, or an underground valve box. Don't force it.
- Connect the compressor to the blowout fitting downstream of the backflow device. Never push compressed air through a pressure vacuum breaker (PVB) or reduced pressure (RP) backflow. The rubber seals inside can melt from the heat.
- Keep the pressure between 40 and 80 psi. CSU lists 80 psi as the maximum for rigid PVC and 50 psi for flexible black polyethylene pipe.
- Run one zone at a time, the same way you water. Two short cycles per zone work better than one long one. Once a zone is dry, stop. Air moving through dry pipe builds friction and heat.
- Leave the backflow ball valves and test cocks half open for the winter so they don't trap water and split.
- Leave the controller plugged in. CSU says the transformer's heat helps keep moisture out.
- Wear eye protection, and keep pets inside. The whistling can spook them.
Where DIY usually goes wrong is the compressor. A small garage compressor often can't move enough air, so it pushes some water out and then rides over the rest. CSU's sizing rule is gallons per minute per zone divided by 7.5 equals the CFM you need. Too much pressure can blow nozzles off. If you don't know your pipe type or zone flow, that's a good sign to hand it off.
How much does a sprinkler blowout cost with No Mow Worries?
Since October 8, 2026, we offer sprinkler blowouts, done by a trusted irrigation partner we work with. Pricing is simple:
- $95 covers up to 6 zones.
- $10 per zone after 6. An 8-zone system is $115.
Not sure how many zones you have? Your controller usually shows it. You can also pick "Not sure" on the form and we'll count them when we're out there. Book a sprinkler blowout through our quote form and we'll confirm your date. We're rated 4.9 on Google from 77 reviews (as of October 2026), and we'd be glad to take this one off your list.
Common questions
Residential customers must stop irrigating by October 15. Spray irrigation stays prohibited through April 30, under the ordinance Aurora City Council passed on September 28, 2026.
The National Weather Service lists Denver's average first freeze as October 7. Recent first freezes were October 18, 2025, October 25, 2024 and October 13, 2023.
CSU Extension says yes. Drain valves rely on gravity, and buried pipe settles into low spots that hold water. Systems with electric valves must be blown out with air.
CSU recommends 40 to 80 psi, with 80 psi the maximum for rigid PVC and 50 psi for flexible black polyethylene pipe. Never blow air through a PVB or RP backflow device.
Yes. Hand-watering trees and shrubs is allowed year-round in Aurora. The shutoff applies to spray irrigation.
With No Mow Worries it's $95 for up to 6 zones plus $10 for each zone after 6, done by our trusted irrigation partner.
Sources
- Aurora Water, "Aurora adopts new water-saving rules" (Sept 29, 2026)
- Aurora Water, Watering Times Restrictions
- CBS Colorado, "New water-saving rules adopted by Aurora City Council" (Sept 29, 2026)
- Denver Water, end of lawn watering season Oct 1, 2026
- NWS Boulder, Denver's Fall/Winter/Spring Statistics
- CSU Extension, Preparing Your Sprinkler System for Winter (fact sheet 4.719)
- PlantTalk Colorado 2205, Winterizing Sprinkler Systems