It is the end of September and your sprinklers are probably still running three days a week. Nobody is thinking about frost yet. But the average first freeze in Atlanta lands on November 13, according to the National Weather Service office in Peachtree City, and across northeast Georgia it can come as early as mid-October. That gives you about six weeks, and the first freeze is an average rather than a promise. Some years it arrives two weeks early on a clear, still night when the temperature drops further than the forecast said it would.
Six weeks is plenty of time. It is also exactly long enough to forget.
What actually breaks
Almost nothing underground. The lateral lines running out to your heads sit deep enough in Dunwoody clay that they rarely freeze solid, and the clay itself holds heat better than sand does. The damage happens in the eighteen inches of pipework you can see.
On most houses around here that is a pressure vacuum breaker on a riser, knee height, usually tucked beside the meter or on a side wall where nobody looks. Brass body, plastic bonnet on top, two small test cocks with screwdriver slots. The bonnet holds a poppet and a spring, and it holds water that sits above the shut-off. When that water freezes it expands upward against the plastic, and the bonnet splits along the seam. You will not know until March, when you turn the system on and the thing fountains into the shrubs.
The other casualty is any valve box that has filled with water. Red clay drains slowly, and a box with three inches of standing water in it is a block of ice around a solenoid on the coldest night of the year. If your boxes hold water in fall, that is a drainage problem rather than an irrigation one, and it is worth solving before it becomes both.
Draining beats wrapping
The most common mistake is the foam cover on its own. People pull an insulated pouch over the backflow in November, feel organized, and crack it anyway. Insulation slows heat loss. It does not remove the water, and it is the water that does the damage. Sprinkler Warehouse’s own guidance puts it plainly: insulation alone usually is not enough, because trapped water expands regardless of what is wrapped around it.
So the order matters. Drain first, then wrap.
How we do it
You can shut off your sprinkler system yourself in about twenty minutes on a normal house:
- Close the isolation valve below the backflow. If it is a ball valve with a lever, turn it a quarter turn so the handle sits across the pipe.
- Open both test cocks a quarter turn with a flathead. Water will dribble out of the upper one for a minute. Let it finish.
- Leave the test cocks and the isolation valves at forty-five degrees. Half open. Any water that finds its way back in has somewhere to expand into instead of pushing on a fitting.
- Open the manual drain valves if the system has them at its low points. Plenty of systems built here in the last twenty years do not, which is why step three matters.
- Then insulate the body and both exposed sides with foam pipe wrap and a cover. Not a towel. A wet towel in January is worse than nothing.
- Set the controller to Off, not unplugged. The Off position keeps the clock running and holds your program, so in April you are turning a dial rather than rebuilding a schedule you no longer remember.
Do you need a blowout in Georgia?
Less often than the internet suggests. Compressed-air blowouts are standard practice where frost drives two or three feet down and buried pipe genuinely freezes. That is not Dunwoody. Here the buried pipe is usually fine, and a blowout run at too high a pressure will wreck seals and gears in heads that would have survived the winter untouched.
We blow out systems where there is a reason to: a shallow line under a driveway that was laid too high, a main that runs along the face of a foundation wall, a house that sits empty over the winter. Otherwise we drain the exposed work, protect the backflow and leave the buried system alone. Doing less, correctly, is usually the right answer.
The part that saves water
Turning the controller off in October rather than January is the bit with the biggest effect, and it costs nothing at all.
A bermuda or zoysia lawn is heading into dormancy now. It browns off, it stops growing, and it stops drinking. A controller still firing twice a week through November and December is putting water on grass that has no use for it, usually in the early morning when it is cold enough that it just sits there. Tall fescue is a different animal and will keep growing into the cool weather, so fescue lawns want occasional water later into the fall, but even those want far less than the summer program delivers.
We shut controllers down as part of the fall maintenance round, and the water saved between the last warm week and the spring startup is one of the least glamorous and most effective things we do all year. There is no clever technology in it. It is a dial.
If you do one thing
Go and look at your backflow this weekend. Find it, see whether it is brass and above ground, see whether anything is already wrapped around it, and check whether the valve boxes nearby are holding water after the last rain. That five-minute walk tells you whether this is a job you can do with a screwdriver in October or a call you will be making in March.
If you would rather we handled it, fall shutdowns are part of what we do across Dunwoody, Sandy Springs and Brookhaven, and it is a short visit. Get in touch and we will put you on the list before the first cold snap. More seasonal notes like this one live in our guides, alongside what we do about watering and lawn care the rest of the year.
Freeze dates from the National Weather Service, Peachtree City (weather.gov/ffc/frostfreeze).
