Thornton blowout slots fill up fast every fall. If you're in Thornton, booking a week or two early is the surest way to get the day you want.
Newer neighborhoods north of 136th tend to have larger multi-zone systems with the backflow preventer close to the foundation. Older lots off Washington and around 88th often have simpler systems, but the backflow preventer still has to be drained correctly or it can crack over the winter.
When to book in Thornton
Book from late September through October, before the first hard freeze. A single light frost usually isn't the problem — a hard freeze, with several hours well below 32°F, is what cracks backflow preventers and lines. If one is in the forecast and you haven't booked, call (720) 818-5569.
What every Thornton blowout includes
- Shut off & isolate — The irrigation supply valve is closed and the system is isolated from your house water.
- Blow out every zone — Compressed air at a regulated pressure, zone by zone, until the heads run dry. Drip zones get lower pressure.
- Protect the backflow — The backflow preventer is drained and its test cocks left partly open so trapped water can't crack the body.
- Controller off — The controller is set to off for the season so nothing tries to run on a frozen system.
- Photos of anything off — Cracked heads, leaking valves, or a failing controller get photographed and texted to you, so it's handled before spring.
You don’t need to be home. Tell us where the shutoff, backflow preventer, and controller are, leave any gate unlocked, and we’ll text you when it’s done.
You get the price when you book, before any work starts. It depends mainly on how many zones your system has.
Why not just turn the water off?
Shutting the supply valve doesn't remove the water already sitting in the pipes, valves, and backflow preventer. That water freezes, expands, and cracks things — and you usually find out in spring, when the system won't hold pressure or the backflow sprays when you turn it on.
Spring startup
When it warms up, we bring the system back the right way: slow refill, every zone checked, heads adjusted, and the backflow device checked. Book a spring startup.
More in Thornton
Need other plumbing work while we're there? See water heater repair and replacement in Thornton, backflow testing in Thornton, drain cleaning in Thornton, water softeners in Thornton, and all plumbing services in Thornton. We also do sprinkler blowouts in Denver, Cherry Creek, Arvada, Golden, Lakewood, and across the Denver metro.