Outdoor faucet covers for the first freeze

How to choose

Do the free steps first

Take off the hose and anything else on the spout, including splitters and timers.^{1 3 9} Close the faucet's shutoff valve indoors, which is usually near the faucet in older homes and beside the main water valve in newer ones.¹ Then open the outdoor faucet to drain the line. With the indoor valve closed, leave the handle open all winter, as Frost King advises.¹

University of Illinois researchers found that ice blocks a pipe first, then pressure builds in the water trapped behind it. In a test on copper pipe in an unheated attic, it rose to about 4,000 psi before the pipe burst.^{13 14} An open, drained faucet leaves no water sealed in, and a cover can't do that for you.

Check that the line really drained

If little or no water comes out, the line may still be full. Some faucets have a built-in anti-siphon part called a vacuum breaker, and screw-on ones work the same way. Minnesota home inspector Reuben Saltzman warns that these can keep air out, so water may not drain.¹⁵

Take a screw-on one off in the fall, or adjust it to let air in. For a built-in one, the maker suggested taking the faucet's bonnet, the housing around the stem, apart with a wrench.¹⁵ A cover won't fix a line that's still full.

Find out if your faucet is frost-free

A frost-free faucet has a long tube, and its valve sits inside the warm part of the house. Water in the tube runs out when you shut it, as long as nothing blocks the spout and the faucet slopes down toward the outside.¹⁶ Homes built in the past 30 years likely have them, but check yours rather than assume.⁹ A standard faucet keeps water right at the cold wall, so a cover matters more there.³

On a frost-free faucet, the hose is what counts. A hose left on stops the tube from draining, and the tube can split behind the valve, so almost nothing leaks until the faucet runs again.¹⁶ In spring, have someone watch the inside wall or basement the first time you turn it on.¹⁷

If you have no indoor shutoff

Then you can't drain the line, and the cover is your only layer. Fit one, and follow your water utility's advice during a cold spell. Austin Water, for example, says to let faucets drip at a trickle during a one or two day freeze.⁸ Plan on having a plumber add a shutoff or a frost-free faucet.

Finish before the first hard freeze

Unprotected pipes generally start to freeze when it drops to 20 degrees Fahrenheit outside, according to an insurance research group.^{18 19} That figure is for pipes in buildings, not metal sticking out of a wall in the wind, so treat it as a danger sign and not a safe limit. Faucets on a shady or north side can freeze when the rest of the yard is warmer.⁹

If you use the faucet during winter, the line refills. Drain it again and put the cover back.⁹

Don't put heat tape under a cover

Electric heat tape carries a fire risk that a passive cover doesn't. In 1989 the Consumer Product Safety Commission estimated some 3,300 home fires a year involving heat tapes or cables, warned against overlapping tape unless the maker allows it, and said too much insulation can cause a fire.²⁰ CPSC also said to insulate over heat tape only if the maker advises it, and then with a non-flammable material such as fibrous glass, so don't put heat tape under a foam cover.²⁰

How many you need

You need one cover per outdoor faucet. Measure each faucet with its handle before you order, since sizes vary by listing, and check whether the listing is for one cover or a pack.²