Every September I tell myself I will winterize the sprinklers before the first freeze, and every year I am out there at dusk in a coat, muttering, because I waited too long. This year I wrote it on the calendar. Here is the schedule so you beat me to it.

When to do it

Shut down the system before the ground freezes. For most of the US, that means late September through mid November, depending on your zone. A good rule: do it two to three weeks before your area’s first expected frost date. A hard freeze in the 20s will crack pipes and heads.

Why you cannot just turn it off

Turning off the timer is not enough. Water left in the lines freezes, expands, and splits the pipes underground. You find out in spring when the yard turns into a swamp.

How to winterize

1. Shut off the water supply to the system, usually a valve near the house.
2. Drain the backflow preventer if it has one.
3. Open the drain valves at the low points and let water run out.
4. Set the timer to off or rain mode so it does not run all winter.

Blow it out for extra safety

If your lines run shallow or you live somewhere brutal, rent an air compressor and blow out the lines. Many lawn care companies do this for a small fee, and it is cheaper than a spring repair bill. I paid a guy forty bucks last year and skipped the whole ordeal.

One more thing

Disconnect hoses from outdoor spigots and drain them too. A frozen hose bib can burst and flood your basement wall. Five minutes now saves a plumber visit in January.