Over the next few weeks we'll be doing fall cleanups and getting properties ready for winter. For homes in Shrewsbury with an in-ground sprinkler system, that list includes the irrigation lines, because any water still sitting in them when the ground freezes can do real damage.
Below is how we approach it, and where the university extension guides draw the line on doing it yourself.
Why the lines need to be empty before a hard freeze
Most things shrink as they get cold. Water doesn't. Colorado State University Extension explains that it expands by about one-eleventh as it turns to ice, so 11 cubic feet of water becomes roughly 12 cubic feet of ice. That force is enough to burst pipes and fittings and to split sprinkler and pump cases.
The University of Minnesota's turfgrass team singles out exposed pipe above ground, like the piping around a backflow preventer. Usually nobody sees the damage until spring startup.
What a blowout is, and why gravity isn't enough
A blowout means clearing the water out of the irrigation lines with compressed air before winter.
Some systems also have manual or automatic drain valves, but CSU Extension doesn't recommend relying on them alone. Buried pipe shifts over the years, water collects in the low spots, and once the lines are underground there's no way to look inside and check. Systems with electric valves need air to push out the water sitting above each valve's diaphragm. The same guide stresses that air volume matters as much as pressure, and that the lines should be cleared one zone at a time, the way most systems run when they water.
Plan it alongside the fall cleanup, not after the first snow
Our advice to neighbors this time of year is simple: don't wait for the first snowfall to get your property ready. That goes for the sprinkler system as much as for the leaves.
There's no single date that fits every property, so we'd rather have the conversation early. Winterization and Seasonal Cleanup are separate services, and neither is added to the other automatically. Still, if you're already planning a fall cleanup, that same estimate request is a good moment to mention the irrigation system. One visit, two questions answered.
What we confirm once we see the system
Our irrigation work covers installation, startup, repairs, coverage checks, and winterization. No two systems are set up quite alike, so we don't start from a standard package.
At the visit we walk the areas you want ready for winter, talk through the system with you, and check access such as gates or slopes. Whether your job includes a blowout is something we confirm after we've seen the system; it isn't included automatically. Then we outline the scope and the timing, and the next step toward a proposal is clear. The Winterization page goes into more detail.
What to have ready for the estimate visit
UMN's guide notes that the irrigation shutoff valve sits somewhere between the water supply and the backflow preventer. It can be in the basement, a crawlspace, or an underground valve box outside, so knowing where yours is saves time. A few other details help us too:
- Where the controller is, so we can see how the zones are set up.
- Photos of the system and of the areas you want ready for winter.
- Gates, slopes, drainage problems, pets, or anything you'd like left alone.
Why the extension guides warn against a home compressor
UMN's turfgrass team is direct about it: it doesn't recommend that homeowners blow out their own systems. Most consumer compressors can reach the pressure but not the volume of air, and that leaves water behind in the lines.
CSU describes the opposite risk. Too much pressure can blow sprinkler nozzles off. Running too many zones at once heats the pipe and fittings through friction, which can damage them or shorten their life.
A shop compressor in the garage isn't the right tool for this.
Request your estimate in Shrewsbury
Shrewsbury is on our service-area list, with Clinton as our home base. Availability depends on the address, the season, the scope, and our current schedule, so we confirm it with you directly.
Request your free estimate in Shrewsbury before the first snow, and tell us about the sprinkler system when you do.