Almost everything written about winterizing irrigation systems on the internet is written for a climate Houston does not have. It describes draining the whole system, blowing the lines clear with a compressor, and shutting down for four months. Following it here is a lot of work and a small amount of unnecessary risk. What this metro actually needs is much narrower, and it takes an afternoon at most.
The shutoff below the backflow assembly. This is the step that does most of the work, because it stops the assembly being resupplied with water from the street. Everything downstream stays as it is; buried pipe is not the problem.
With the supply closed, the water still standing inside the assembly is what cracks it. On a pressure vacuum breaker, opening both test cocks and setting the two shutoff handles to roughly forty-five degrees lets that water out and lets air in behind it. This is the step people skip, and skipping it means insulating a body that is still full.
Foam pipe sleeve on the exposed riser pipe, then insulation over the body and bonnet, then something waterproof over that. The detail matters enough to have its own page.
The fourth step has nothing to do with pipe: switch the controller off, or into a long rain delay. A zone that runs at four in the morning during a freeze puts a sheet of ice across a sidewalk or a road, and in an area with curbside parking that is a genuine hazard rather than a nuisance. Some controllers and combination sensors handle this automatically with a freeze cut-out; most systems in this metro do not have one.
Once night temperatures start dropping into the forties and the lawn has stopped growing hard. Nothing is lost by being early — a St Augustine lawn in a Houston November needs very little supplemental water, and what it does need can come from a hose on a warm week.
Undo it when the risk of a hard freeze has passed, which in this metro is generally by the end of February. Re-opening matters as much as shutting down: the isolation valve gets opened slowly, because a mainline that has been drained refills at high velocity and can break fittings and blow heads off risers. That is a spring startup, and it is a good moment to look the assembly over in daylight.
Most of it is not. Closing a valve, opening two test cocks and putting a foam sleeve and a cover over an assembly is a homeowner job by any reasonable measure, and a page that pretended otherwise would be selling something. The materials cost is small and the whole thing is done in less time than it takes to get a quote.
Three situations genuinely change that answer. A property with several assemblies, or a commercial site with a large or reduced-pressure-zone assembly, is a different scale of job. An owner who is not on site — a rental, a second property, a house being sold — needs someone to actually go and do it. And an assembly that has already been through a freeze and been repaired is worth having looked at before winter rather than wrapped over.
The other reason to have an irrigator do it is bundling: winterizing at the same visit as the autumn check means one call-out fee instead of two, and October is the month of the year they can actually get to you.
No, and this is the main way northern advice misleads here. Soil temperature at irrigation pipe depth on the upper Gulf Coast does not reach freezing during the events this region gets. Buried laterals, mainline and in-ground valves come through untouched. What fails is what is standing in the air, and there is exactly one of those on most systems.
That is the other exposed piece and it does need attention — the vertical riser feeding the assembly, and the horizontal section on the far side of it, are both above grade. Foam pipe sleeve on both, taped at the joins, is the whole answer, and it costs a few dollars.
It can, and many people do, and most winters nothing happens. That is the trap: the practice looks fine for three years and then costs several hundred dollars in one night. If a system is going to be left in service through the winter, at minimum the assembly should be insulated and the controller should not run during a freeze.
Less than people assume. Insulation slows heat loss; it does not add heat. Through a short overnight freeze, a well-wrapped assembly full of water will usually survive on its residual warmth. Through the kind of multi-day event this region saw in February 2021, it will not — the whole thing simply reaches ambient temperature eventually. Draining first is what makes the wrap reliable rather than hopeful.
Materials, order, and the mistake that traps water in.
Why the compressor step in northern guides does not apply.
What to check once it warms up, in order.
Undoing all of this properly in March.
October and November are the one stretch of the year with slack in the schedule. Say how many assemblies the property has and where in the metro it sits.
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