What freeze does to an irrigation system
Ice takes up more room than water, and irrigation lines, the small fittings at each valve and the backflow body are not built to hold that pressure. A crack does not announce itself in winter. You find it in spring when a zone runs and water shows up where it shouldn't, or doesn't show up at all. The backflow assembly sits above ground, so it is the part most exposed to the cold. Getting the water out of every zone, and out of the assembly, is the whole job.
How a blowout works
We connect an air compressor to the system and close the backflow isolation valves first, so compressed air does not pass through the backflow device. Then we go to the controller and open the zone that is highest in elevation and farthest from the compressor. Air goes in gradually, never all at once, because a sudden surge is hard on fittings and valves. The compressor is sized to the airflow demand of your largest zone, and a pressure-regulating valve keeps the pressure within limits. We work through the remaining zones one at a time.
What a blowout costs
A residential blowout on a system with five or six zones runs $100 to $130. Quote us your zone count on the phone and we'll give you the usual range for that size, then set the final price once we've walked the system. Zone count drives the price because we run each zone on its own and let it clear before moving to the next. A system with more zones than that takes more time, and the price follows.
What we do on site
Each zone runs until the heads are putting out air and no water. While we are working through the zones, we watch for a valve that doesn't close fully or a head that doesn't pop up. Anything like that gets pointed out to you before the truck leaves. Any repair is quoted separately, and you have the price before we start that work. Spring is wet in Denton, and May is the rainiest month, so the system needs to be empty and intact all winter so it can run when that rain tapers off.
When to book it
Book it before freezing temperatures show up in the forecast, while there is still water in the lines. If you added a zone or changed the layout since the last winterization, mention it when you book. New zones or repaired sections are easy to miss if the layout isn't fully known, and we want every one of them cleared.
What to Expect to Pay
These ranges are here to help you budget, and the details of your job set the actual number.
$150–$250
Related Services
What to Expect
For work like this, these are the main parts:
- After removing the water, disconnect the compressor and release remaining air pressure; leave backflow isolation valves partly open and open the test cocks.
- Shut off the irrigation water supply before starting the blowout.
A few minutes on the phone covers most of it, no hard sell.