When to Winterize Sprinklers and Outdoor Faucets in Your State

Water expands by about nine percent when it freezes, and it does not care whether it is in a lake or a half-inch copper pipe. The most expensive version of this lesson is the hose left connected through the first hard freeze. Ice forms in the hose and backs up into the faucet. The pipe splits behind the wall, where nobody notices until the spring thaw. The fix takes ten minutes. Here is when to do it in every state.

Two Jobs, Two Deadlines

By the first frost: hoses off, drained and stored. Sprinkler timers switched off. This is the easy one and it removes the main cause of burst faucets.

By the first hard freeze: the irrigation system blown out or drained, and any outdoor faucet with an interior shut-off valve closed inside and opened outside so the stub of pipe is empty. A single night at 28F or lower for several hours is enough to freeze standing water in an exposed pipe. Typical hard freeze timing for every state is in our first hard freeze guide; the table below pairs it with the frost date.

Winterizing Deadlines by State

State	Hoses off by (average first frost)	Irrigation blown out by (typical first hard freeze)	Earlier or later
Alabama	November 13	Late November to early December	Earlier in the Tennessee Valley, later on the Gulf
Alaska	September 14	Late September to early October	Fairbanks and the Interior freeze hard by mid September
Arizona	October 1	Mid October (high country); rare in Phoenix and Tucson	Low deserts may go whole winters without 28F
Arkansas	November 4	Mid to late November	Ozarks run one to two weeks earlier
California	November 26	Mid December (inland valleys); rare on the coast	Sierra foothills and high desert freeze in October
Colorado	October 7	Mid to late October	Mountain towns freeze hard in September
Connecticut	October 10	Late October to early November	Shoreline runs about two weeks later
Delaware	October 30	Mid November	Coastal Sussex County a week or so later
Florida	December 16	Late December to January (north); rare central and south	Miami and the Keys almost never reach 28F
Georgia	November 19	Late November to early December	North Georgia mountains freeze hard by early November
Hawaii	No frost	None at sea level	Only the summits of Mauna Kea and Haleakala freeze
Idaho	October 12	Mid to late October	Mountain valleys freeze hard in September
Illinois	October 28	Late October to mid November	Northern counties earlier, southern tip later
Indiana	October 15	Late October to early November	Lake Michigan shore a week later
Iowa	October 12	Late October	Northwest corner a week earlier
Kansas	October 28	Early to mid November	Northwest Kansas two weeks earlier
Kentucky	October 30	Early to mid November	Eastern mountains earlier
Louisiana	November 22	Early to mid December (north); rare on the coast	New Orleans can skip 28F in a mild winter
Maine	October 8	Mid to late October	Caribou and the North Woods freeze hard by early October
Maryland	November 12	Mid to late November	Western mountains in late October
Massachusetts	October 27	Early to mid November (coast); late October (Worcester hills)	Cape Cod the latest in the state
Michigan	October 20	Late October to early November	Upper Peninsula freezes hard by mid October
Minnesota	October 8	Mid to late October	International Falls and the Arrowhead by early October
Mississippi	November 15	Late November to early December	Gulf Coast later still
Missouri	October 29	Early to mid November	Northern Missouri a week earlier
Montana	September 29	Early to mid October	Great Falls and the high line by late September
Nebraska	October 9	Late October	Panhandle a week or two earlier
Nevada	October 14	Late October (north); rare in Las Vegas	High desert valleys freeze hard in early October
New Hampshire	September 22	Early to mid October	White Mountains by late September
New Jersey	November 5	Mid to late November	Northwest hills in late October
New Mexico	October 29	Early to mid November (Rio Grande valley)	Santa Fe and the high country by mid October
New York	October 7	Late October (upstate) to late November (NYC)	Adirondacks and Tug Hill by early October
North Carolina	November 7	Mid to late November	Asheville and the mountains by early November
North Dakota	October 1	Early to mid October	Northwest corner in late September
Ohio	October 18	Late October to early November	Lake Erie shore a week later
Oklahoma	November 5	Mid to late November	Panhandle in late October
Oregon	November 19	Early to mid December (west); mid October (east)	Bend and the high desert freeze hard in early October
Pennsylvania	November 6	Early November (Pittsburgh) to late November (Philadelphia)	Northern tier and the Poconos by mid October
Rhode Island	October 28	Early to mid November	Block Island later
South Carolina	November 1	Mid to late November (inland); early December (coast)	Upstate earlier
South Dakota	October 5	Mid October	Black Hills by late September
Tennessee	October 31	Early to mid November	Memphis a week later, the Plateau earlier
Texas	November 17	Early December (Dallas); early November (Panhandle); rare on the coast	Houston and the coast may not see 28F every winter
Utah	October 15	Late October to early November	High valleys by late September
Vermont	October 3	Mid to late October	Northeast Kingdom by early October
Virginia	October 26	Early to mid November	Shenandoah and the Blue Ridge in late October
Washington	November 25	Early to mid December (west); mid to late October (east)	Spokane freezes hard by late October
West Virginia	October 25	Early to mid November	Mountain counties in October
Wisconsin	October 9	Mid to late October	Milwaukee lakeshore a week later, the North Woods earlier
Wyoming	September 27	Early to mid October	Jackson and the mountain valleys by mid September

The second column is the one to put in the diary. Irrigation contractors in the northern half of the country are fully booked for the last two weeks before the typical hard freeze. A slot in the first half of the window is worth more than a cheaper one in the second.

How to Winterize an Outdoor Faucet

• Disconnect the hose, drain it fully and store it coiled indoors or in a shed. A hose left outside full of water will split.
• Find the interior shut-off valve for that faucet, usually in the basement or crawl space on the pipe leading to the wall. Close it.
• Go back outside and open the faucet. Leave it open all winter so any water that gets in can drain or expand harmlessly.
• If the interior valve has a small bleeder cap, open it with a bucket underneath to drain the last of the water.
• No interior valve? Fit an insulated faucet cover (a foam dome, a few dollars at any hardware store). It is not a substitute for draining, but it buys several degrees.
• Frost-free hose bibs (the long-stem type that shuts off inside the warm wall) do not need draining, but they do need the hose removed. A connected hose traps water in the stem and defeats the design.

How to Winterize a Sprinkler System

There are three methods, and which one applies depends on how the system was installed.

• Blow-out (most common): shut the water supply to the irrigation system, connect an air compressor to the blow-out port, and run each zone in turn at low pressure (no more than 50 psi for PVC, 80 psi for poly pipe) until only mist comes out of the heads. Wear eye protection. Most homeowners hire this out; a contractor commonly charges somewhere around 60 to 120 dollars for a residential system.
• Manual drain: if the system was installed with drain valves at the low points, shut the supply and open every drain valve, then open the test cocks on the backflow preventer. Only works on systems designed for it.
• Automatic drain: some systems drain themselves when pressure drops below a threshold. Shut the supply, run a zone briefly to release pressure, and check the low points.

Whichever method, the backflow preventer is the part that breaks. It sits above ground, holds water, and is the first thing to freeze. Drain it, open its test cocks to a 45 degree angle, and if it is exposed, wrap it. A replacement runs into the hundreds.

If You Get Caught Out

A hard freeze is forecast tonight and nothing is done. Disconnect the hoses now, that is the most important single step. Open the outdoor faucets. Shut off the irrigation controller and the system’s supply valve. Let a cold tap drip indoors overnight on any pipe run along an exterior wall.

Then book the blow-out for the next mild day. One night rarely freezes a buried line, but a buried line full of water will not survive a week of them.

Frequently Asked Questions

At what temperature should I winterize my sprinklers?

Before the first hard freeze, 28F or lower for several hours. A light frost at 32F will not freeze buried lines, but it is the signal to book the blow-out, because the hard freeze typically follows within two to three weeks.

Do I need to disconnect my hose in winter?

Yes, everywhere a frost is possible. A connected hose holds water against the faucet, and when it freezes the ice pushes back into the pipe inside the wall. This is the most common cause of a burst pipe and it affects frost-free faucets too.

Can I blow out my sprinkler system myself?

Yes, with a compressor that delivers enough volume (around 10 cubic feet per minute for a typical home system) and care with the pressure: 50 psi or less for PVC, 80 psi for polyethylene. Run one zone at a time, stop when mist appears, and wear eye protection. Many people hire it out for the price of an hour’s labor.

What happens if I do not winterize my sprinkler system?

Water in the lines and heads freezes and expands, cracking pipes, fittings and the backflow preventer. The damage shows up in spring as wet spots, dead zones and a backflow unit that leaks under pressure.

When should I turn the outdoor water back on?

After the last spring frost for your area. Open the supply slowly to avoid a pressure surge, and check the backflow preventer and each zone for leaks before setting the timer.

Are these dates a forecast?

No. They are long term averages of first frost and first hard freeze from NOAA climate normals. Any autumn can run early, so a mid-window appointment is safer than a late one.

Read Next

• When Is the First Hard Freeze in Your State?
• When Should You Stop Watering Your Lawn in Fall?
• How to Winterize a Lawn Mower and Outdoor Power Equipment
• 10 Things To Do Before Turning On Your Heat This Fall