Keep indoor pipes from freezing — and thaw them without a flame

Where indoor pipes actually freeze

Water expands as it freezes. The American Red Cross: that expansion puts tremendous pressure on metal or plastic pipe, and expanding water can break the pipe no matter how strong the container looks. The lines that freeze most often, on that same page, are outdoor hose bibs, pool and sprinkler supply, pipes in unheated interiors (basements, crawl spaces, attics, garages, kitchen cabinets), and pipes against exterior walls with little or no insulation.

Illinois Extension puts a published leak size on a rupture: an eighth-of-an-inch crack in a pipe can release up to 250 gallons of water a day. Know where the house shutoff is before you need it.

Four indoor moves before the cold snap

1. Open kitchen and bathroom cabinet doors so warmer air can circulate around the plumbing. Red Cross: move harmful cleaners and household chemicals up out of the reach of children. Illinois Extension: this is for uninsulated pipes under a sink or appliance near an outer wall.
2. Let water move in the exposed lines. Red Cross: when it is very cold outside, let the cold water drip from the faucet served by those pipes — even a trickle helps. FEMA: allowing faucets to drip slowly keeps water moving, reducing the chance of freezing. Illinois Extension: at night, let hot and cold water trickle from a faucet on an outside wall.
3. Hold the heat. Red Cross: keep the thermostat at the same temperature day and night during a freeze; a higher bill is cheaper than a burst. If you go away, leave the heat on, set no lower than 55°F. Illinois Extension: heat left on, no lower than 55 degrees; if you will be gone, have someone check daily or drain and shut off the system (except indoor sprinklers).
4. Insulate the cold runs in attics, basements, crawl spaces, garages, and under cabinets. Red Cross: both hot and cold pipes in unheated spots. Pipe sleeve products, or even ¼ inch of newspaper on exposed pipe in places that do not usually see long stretches below freezing. Keep the garage door closed if supply lines run through the garage.

Minnesota Extension’s winter safety sheet is shorter on this topic: frozen pipes can burst; drain and shut off lines you do not use often in winter, especially those that lead outside. That last clause is the outdoor faucet job.

Heat tape is optional — and a fire product

Red Cross: consider UL-listed heat tape, heat cable, or similar material on exposed water pipes. Illinois Extension: wrap with UL-approved heat tape. Neither agency names a brand. The CPSC does name the failure mode.

In its 1996 re-issue of heat-tape guidelines, the CPSC estimated about 1,500 fires, 10 deaths, and 100 injuries each year from faulty electric heat tapes. That estimate is from that release — do not treat it as a current annual census. The same guidance: replace uncertified heat tapes more than three years old with tape certified to UL, CSA, or Factory Mutual (FMRC) standards; check instructions when you change type or brand; apply tape directly on the pipe, never on top of insulation; do not cover the tape with insulation unless the manufacturer says to, and then use nonflammable insulation such as fiberglass, not foam or vinyl that can catch from a failing tape; keep the end cap sealed and off the ground; always use the three-prong plug in a three-prong outlet and a GFCI; do not wrap tape over itself unless the instructions specifically allow it; do not use water-pipe tape on gutters, driveways, or fuel lines.

Manufacturer instructions win over this page. If you can insulate the cavity or move the pipe instead, that is the Red Cross relocation option — and it avoids a product the CPSC still treats as a fire hazard when it is old or misinstalled.

If a pipe is already frozen

Red Cross: if you open a faucet and only a trickle comes out, suspect a frozen pipe. Likely spots are against exterior walls or where the service enters through the foundation.

1. Keep the faucet open. As ice melts, water flowing through the pipe helps finish the thaw.
2. Apply heat to the frozen section with an electric heating pad wrapped around the pipe, an electric hair dryer, a portable space heater kept away from flammable materials, or towels soaked in hot water. The Red Cross does not publish a clearance for that heater. Minnesota Extension: keep a space heater at least three feet from furniture and drapes, with an automatic shut-off and a non-glowing element, never on furniture or near water, and never leave children unattended near one. FEMA’s storm post: keep anything that can burn at least three feet from heat sources such as fireplaces, wood stoves, or candles.
3. Keep heating until full water pressure is back. Then check every other faucet. One freeze often means another.

Call a licensed plumber if you cannot find the frozen area, cannot reach it, or cannot thaw it. Illinois Extension: if a pipe bursts, shut the water off, call a plumber, and call your insurance agent — and watch for electric shock in standing water.

STOP — never open flame

Illinois Extension publishes it in those words: never try to thaw a pipe with an open flame or torch. The Red Cross names the same class of devices: do not use a blowtorch, kerosene or propane heater, charcoal stove, or other open flame device. Ready.gov and Minnesota Extension separately warn not to heat the house with a stove or oven — fire and carbon monoxide, not a thaw method.

What the sources actually say

Prevention and thaw sequence: American Red Cross. Drip during a storm: FEMA. Night trickle, 55°, ⅛″ / 250 gallons, and the torch STOP: Illinois Extension. Outdoor unused lines: Minnesota Extension. Heat-tape fire caveats: CPSC 1996.

Questions people actually ask

Should I leave a faucet dripping?

When it is very cold, the American Red Cross says to let cold water drip from the faucet served by exposed pipes — even a trickle moving through the pipe helps keep it from freezing. FEMA’s winter-storm safety post says the same: drip faucets slowly so water keeps moving. Illinois Extension adds a night trick for faucets on an outside wall: let both hot and cold trickle. Drip the lines that run through cold spaces, not every fixture in the house.

How low can I set the heat?

The Red Cross freeze-prevention floor if you leave during cold weather is no lower than 55°F, with the heat left on. Illinois Extension matches that: heat on, set no lower than 55 degrees, and if you are away either have someone check daily or drain and shut off the water (except indoor sprinklers). Keep the thermostat at the same temperature day and night while a freeze is on, rather than a nighttime setback. Minnesota Extension’s winter energy sheet aims at 68°F or lower to cut bills — that is a cost target, not freeze protection. Do not treat 68°F as a pipe-safe number.

Is heat tape a good idea?

The Red Cross lists UL-listed heat tape, heat cable, or similar products on exposed pipes as one option, along with pipe sleeves. Illinois Extension likewise says wrap with UL-approved heat tape. The CPSC’s 1996 heat-tape guidance is the caveat: old, uncertified, or poorly installed tape is a fire problem — about 1,500 fires, 10 deaths, and 100 injuries a year from faulty electric heat tapes in that estimate. Replace uncertified tape more than three years old with tape certified to UL, CSA, or FMRC standards; put it on the pipe, not on top of insulation; do not cover it unless the manufacturer says to; use a grounded three-prong plug and a GFCI; do not overlap unless the instructions allow it.

A faucet is only a trickle. How do I thaw the pipe?

Suspect a freeze. Keep that faucet open. The Red Cross: apply heat with an electric heating pad wrapped around the pipe, a hair dryer, a portable space heater kept away from flammable materials, or towels soaked in hot water — until full pressure returns. Illinois Extension: never thaw with an open flame or torch. The Red Cross names the devices not to use: blowtorch, kerosene or propane heater, charcoal stove, or other open flame. If you cannot find the frozen section, cannot reach it, or cannot thaw it, call a licensed plumber. Check the other faucets; one freeze often means more.

Does this replace shutting off the outdoor faucets?

No. This page is the indoor side — cabinets, drip, heat, insulation, and thaw. The hose bib is the short run through the wall. Minnesota Extension: drain and shut off pipes you do not use in winter, especially those that lead outside. Illinois Extension: disconnect garden hoses and shut off and drain the lines to outside faucets so ice does not start in that short span just inside the house. Do that job on the outdoor-faucet guide; do not mix the two procedures here.

Related

• Outdoor faucet shutoff — disconnect the hose, close the indoor shutoff, drain, leave the bib open.
• First frost — the same seasonal trigger, tracked as a date that moves.
• Weatherstripping — Ready.gov’s caulk-and-strip half of keeping cold off the walls that hide pipe.
• HVAC service — the heat you are counting on has to actually run.
• December checklist — where a hard freeze lands on the calendar.

Sources

• American Red Cross — Preventing & Thawing Frozen Pipes: which pipes freeze; cabinets; cold drip; same thermostat day and night; 55°F if away; ¼″ newspaper; UL-listed heat tape; thaw with pad, hair dryer, space heater, or hot towels; no blowtorch, kerosene or propane heater, charcoal stove, or other open flame.
• FEMA — 5 Ways to Safely Weather the Storm (Jan. 24, 2026): drip faucets slowly; keep burnables at least three feet from heat sources.
• Ready.gov — Winter weather: insulation, caulking, and weather stripping; learn how to keep pipes from freezing; do not heat with a gas stovetop or oven.
• Illinois Extension — Water pipes: ⅛″ crack up to 250 gallons a day; UL-approved heat tape; disconnect hoses / drain outdoor lines; hot and cold night trickle; cabinets; heat no lower than 55°; never thaw with open flame or torch; house shutoff if a pipe bursts.
• Minnesota Extension — Keep your home warm and safe in winter: drain and shut off unused winter lines, especially those that lead outside; space heaters three feet from furniture and drapes; do not use stove or oven for heat.
• CPSC — Heat tape guidelines (1996): ~1,500 fires / 10 deaths / 100 injuries per year from faulty tape (that estimate); replace uncertified tape older than three years; UL / CSA / FMRC; on-pipe install, GFCI, no overlap unless allowed.

General information, not advice for your specific plumbing. A burst or a pipe you cannot thaw is a plumber’s job.