Dealing With Frozen Pipes: Prevention and Repairs – This Old House

If you’ve ever turned on a faucet during a cold snap and heard nothing but ominous silence, you already know:
frozen pipes are the jump scare of winter homeownership. One minute you’re sipping cocoa, the next you’re
Googling “how much does water damage cost” and eyeing your ceiling for bubbles.

The good news? With a little planning, some basic insulation, and a calm head when temperatures plunge, you can
prevent most frozen-pipe disastersor at least deal with them before they turn your living room into a wading pool.
This guide channels the hands-on know-how of This Old House–style plumbing pros along with practical tips
from insurers, safety organizations, and emergency-prep experts across the U.S., then repackages it in plain English
you can actually use when it’s 10°F and your brain’s half-frozen too.

Why Pipes Freeze and Burst in the First Place

Water is a bit dramatic. When it freezes, it expandsup to about 9% in volume. In a pipe, that expansion builds
pressure. If the ice forms in one area and the pipe is closed off at both ends, that pressure has to go somewhere.
It usually finds the weakest link: a fitting, a joint, a thin section of copper or plastic. That’s where the pipe
splits or bursts.

Pipes are most likely to freeze when:

• They’re in unheated spaces like crawlspaces, garages, attics, or unfinished basements.
• They run along exterior walls with poor insulation.
• Outdoor hose bibs or supply lines to sprinklers aren’t shut off and drained before winter.
• The thermostat is turned down too low, especially overnight or while you’re away.

Older homes and DIY remodels are especially vulnerablethink strange pipe runs through unheated porches, or
bathroom additions where the wall cavity insulation never quite caught up with the plumbing.

How to Tell If Your Pipes Are Frozen

Sometimes a frozen pipe is obvious (hello, bulging tube of doom). Other times, you only get subtle hints. Catching
the problem early can be the difference between a mild scare and a major insurance claim.

Common signs of a frozen pipe

• Little or no water flow from a faucet when temperatures are below freezing.
• Only one fixture or one area affectedfor example, the kitchen sink works, but the upstairs bathroom doesn’t.
• Frost or ice on exposed pipes in basements, crawlspaces, garages, or under sinks.
• Unusual smells or gurgling sounds from a drain or faucet where the line may be blocked by ice.
• Wall feels unusually cold or slightly “humming” where a pipe runs, especially near exterior walls.

If you notice any of these signs during a cold spell, assume a pipe might be frozen and act quicklybefore the ice
expands further or the pipe cracks and then thaws, unleashing a surprise indoor waterfall.

Immediate Steps If You Suspect a Frozen Pipe

First, breathe. Then follow a calm, step-by-step approach instead of trying five random internet hacks at once.

1. Keep the faucet open

If water is still trickling out, leave the faucet open. Running water helps relieve pressure and can speed up
thawing as you warm the pipe. Open both hot and cold taps on a mixer faucet if possible, so both lines can relieve
pressure.

2. Find the likely frozen section

Trace the affected pipe as best you can:

• Check where the line runs through unheated areas (basements, crawlspaces, garages, attics).
• Look inside cabinets on exterior walls under sinks.
• Follow the line from the problem faucet back toward where water enters the house.

Sometimes you’ll see frost, a bulge, or a section that feels much colder than the rest. That’s your prime suspect.

3. Check for leaks or a burst pipe

Before applying any heat, inspect carefully:

• Look for dripping, spraying, or water stains on ceilings or walls.
• Listen for hissing or trickling behind walls.
• Check the area below the suspected frozen section (lower floors, ceilings, or crawlspaces).

If you see active leakingor hear what sounds like water running where it shouldn’tgo straight to your main shut-off
valve and turn off the water supply to the house. This is why every expert tells you to know where that valve is
before winter hits.

Safe Ways to Thaw a Frozen Pipe (DIY Methods)

Thawing pipes is not about brute force. The goal is slow, controlled heating so the ice melts without turning into
steam or overheating the pipe. The pros are unanimous on one key rule:
never use open flamesno blowtorches, no propane heaters pointed at pipes, no candles.

Instead, use these safer methods:

1. Hair dryer method (the classic)

1. Plug in a standard hair dryer and set it to medium or high heat.
2. Start at the faucet end of the pipe (where water will come out) and work your way back toward the frozen section.
3. Move the dryer slowly back and forth along the pipe, keeping it a few inches away.
4. Keep the faucet open so melting ice can escape as water, not build pressure.
5. Continue until full water flow returnsand then keep going a bit longer to make sure the pipe is fully thawed.

Avoid using a hair dryer near standing water, and don’t let the pipe get too hot to touch.

2. Warm towel wrap

For accessible sections of pipe:

1. Soak towels in hot (not boiling) water and wring them out.
2. Wrap the towels around the frozen section of pipe.
3. Replace them as they cool, working from the faucet back toward the coldest part.

This is slower than using a hair dryer but can be safer around tight spaces or older materials.

3. Electric heating pad or space heater

• Wrap an electric heating pad around the pipe and set it to low or medium.
• Or place a portable electric space heater in the room near the frozen section.

Keep flammable materials away, follow the device’s safety instructions, and never leave a space heater unattended.

4. Heat tape or pipe heating cable

For pipes that repeatedly freeze, an electric heat tape or heating cable, installed according to the manufacturer’s
directions, can be a long-term solution. Some products turn on automatically when temperatures drop, giving your
pipes a little heated jacket every time a cold snap hits.

What to Do If a Pipe Bursts

Once a pipe actually splits, your mission changes from “save the pipe” to “save the house.”

1. Shut off the water immediately

Turn off the main water valve to the house. In many homes, this is:

• Near where the main water line enters the basement or crawlspace, or
• In a utility room or near the water heater, or
• At an exterior meter pit in some regions (you may need a special key or tool).

If the burst is on a branch line that has its own shut-off, you might be able to isolate just that section, but in
an emergency, turning off the main is the safest move.

2. Kill power in affected areas (if needed)

If water is dripping near electrical outlets, fixtures, or your breaker panel, switch off power to that part of the
house at the breaker box. Water and electricity are a famously bad duo.

3. Start cleanup and drying right away

The faster you dry things out, the less chance you’ll have mold and long-term damage:

• Mop up standing water with towels, mops, and a wet/dry vacuum if you have one.
• Move furniture, rugs, and belongings out of wet areas.
• Run fans and dehumidifiers, and open windows if outdoor humidity and temperature allow.

4. Call in the pros

A licensed plumber should repair or replace burst sections of pipe, especially if they’re inside walls or ceilings.
For major flooding, a water-damage restoration company can help dry structures thoroughly and reduce the risk of mold.
You’ll also want to contact your homeowners insurance carrier promptly and document damage with photos and videos
before too much cleanup happens.

Long-Term Strategies to Prevent Frozen Pipes

Once you’ve survived one frozen-pipe scareor better yet, before you have oneyou can dramatically lower your risk
with a few smart upgrades and habits.

Insulate vulnerable pipes

Focus first on any pipes that:

• Run through unheated crawlspaces, attics, garages, or overhangs.
• Are near vents, drafty windows, or exterior doors.
• Serve bathrooms or kitchens on exterior walls.

Use foam pipe insulation sleeves, which are inexpensive and easy to cut to length. For tight spaces or odd angles,
self-adhesive pipe wrap or fiberglass insulation with a plastic vapor barrier can help. In very cold climates or
chronically troublesome spots, heat tape plus insulation is often worth the small added cost.

Protect outdoor faucets and hose bibs

• Disconnect and drain garden hoses before the first hard freeze.
• Shut off the interior valve that feeds outdoor spigots (often in the basement or utility room).
• Open the outdoor faucet to drain any remaining water and leave it slightly open.
• Install or use insulating faucet covers to reduce heat loss.
• Consider upgrading to frost-proof sillcocks if you live in a cold region.

Use your thermostat strategically

Many experts recommend:

• Keeping the thermostat at 55°F (13°C) or higher during cold snaps, even if you’re away.
• Avoiding big nighttime setbacks; dropping from 70°F to 60°F might save a little on energy but increase freezing risk.
• Using a smart thermostat with remote monitoring so you can confirm your home is heated during travel.

Is it fun paying to heat a house you’re not in? Not really. Is it more fun than paying for new drywall, flooring,
and furniture? Absolutely.

Know when to drip faucets

When temperatures are forecast to reach the low 20s°F or colderespecially if you have vulnerable lineslet certain
faucets drip at a slow, steady rate. Focus on:

• Faucets served by pipes along exterior walls.
• Fixtures in unheated or less-heated rooms (over garages, in basements, on additions).
• The faucet farthest from your main shut-off valve to keep water moving through the longest stretch of pipe.

Drip both hot and cold lines on single-handle faucets if you can. Moving water is much harder to freeze than water
sitting still.

Seal air leaks and improve insulation

Even well-insulated pipes can freeze if cold air pours in through gaps and cracks. On your next weekend project list:

• Seal gaps around sill plates, vent openings, and penetrations where pipes and wires exit the house.
• Weather-strip drafty exterior doors near plumbing runs.
• Add insulation above crawlspaces and in attics, especially over bathrooms and kitchens.

These upgrades not only protect pipes but also improve comfort and reduce heating billsan excellent two-for-one.

Use smart tech to your advantage

A few relatively affordable devices can give you early warning:

• Smart leak detectors placed near water heaters, under sinks, and in basements can alert your phone if they sense moisture.
• Temperature sensors in crawlspaces or mechanical rooms can warn you if those areas drop to risky levels.
• Smart thermostats let you confirmand adjustyour home’s temperature from anywhere.

Think of them as tiny digital watchdogs guarding your plumbing while you’re out living your life.

Older Homes and Southern Houses: Extra Reasons to Be Careful

Not all houses face equal risk from frozen pipes. Two categories stand out:

1. Older homes

Classic houseslike the ones lovingly rescued on shows such as This Old Houseoften have charming quirks
and slightly less charming plumbing layouts. You might find:

• Pipes run on exterior walls with minimal or no insulation.
• Uninsulated crawlspaces or basements that hover near outdoor temperatures.
• Past DIY renovations where pipes were added in unconditioned areas “just for now.”

A good winter prep checklist for these homes includes a thorough hunt for exposed or poorly insulated pipes and
prioritizing insulation and air sealing where you find trouble spots.

2. Homes in milder climates

In many southern and coastal regions, builders never expected multiple nights in the teens. Pipes may be routed
through attics or unconditioned spaces with minimal protection. As cold snaps become more frequent or severe,
homeowners in these areas are seeing more frozen-pipe damage.

If you live in a “normally mild” climate, treat the first big freeze warning like a fire drill for your plumbing:
insulate, drip critical faucets, protect outdoor spigots, and know where your main shut-off is.

When It’s Time to Call a Pro

There’s no shame in calling a plumber early. In fact, it’s often cheaper than waiting until something bursts.
Get professional help when:

• You can’t locate the frozen section but you’ve lost water to part of the house.
• The frozen pipe is inside a wall or ceiling and not easily accessible.
• You’re unsure if there’s already a crack or leak and don’t want to risk turning the water back on.
• You’ve had repeated freezes in the same area and need a long-term fix (rerouting or re-insulating lines).
• You’re not comfortable using electrical heating methods near pipes.

A pro can not only thaw pipes safely but also recommend upgradeslike rerouting a section, adding valves, or
installing shut-offsthat make future freezes much less likely.

Lessons From the Frozen Front Lines: Real-World Experiences

Advice is great. Stories are better. Here are a few very typical frozen-pipe scenarios (based on real-world patterns
plumbers and insurers see all the time) and the lessons they teach.

The holiday thermostat “oops”

A family heads out of town for the holidays. To “save heat,” they drop the thermostat to 45°F and leave for a week.
A cold front pushes nighttime temps into the single digits. A pipe in the over-garage bathroom freezes and bursts.
No one discovers it until a neighbor notices water running out the garage door.

What they learned: Thermostats should stay at 55°F or higher during serious cold, even when you’re
away. A smart thermostat plus a leak detector might have alerted them before days of water damage piled up.

The “I’ll insulate it next year” basement

A homeowner knows the basement is chilly and the pipes are exposed but figures, “It’s been fine so far.” Then a
colder-than-usual winter hits. One morning, the kitchen faucet barely drips. They go downstairs and find a long
section of copper pipe covered in frost.

This story has two endings:

• Good ending: They catch it early, use a hair dryer, keep the faucet open, and thaw the line without a burst.
• Not-so-good ending: They ignore it, the pipe splits behind a storage shelf, and they only discover it when temps rise and water pours out.

What they learned: Exposed pipes in unheated spaces need insulation before the first deep
freeze, not after the first emergency.

The southern cold snap surprise

In a typically mild climate, a homeowner has water lines running through the attic. Pipes have no insulation because
“it never gets that cold here.” Then an unusual Arctic blast brings several nights below 20°F. They wake up to no
water anywhere in the house.

A plumber eventually finds multiple frozen lines in the attic and recommends rerouting or insulating, plus adding
attic ventilation improvements. The repair bill stings, but not as much as the thought of a major attic flood would
have.

What they learned: If your pipes are in places that can hit freezing temperaturesattics, crawlspaces,
exterior wallsyou need protection, even if your winters are usually mild.

The cautious DIY thaw

Another homeowner does just about everything right. They notice low flow at an upstairs faucet, immediately suspect
a freeze, and:

• Leave the faucet open.
• Locate the most likely frozen section in a chilly knee wall space.
• Use a hair dryer from the faucet side back toward the coldest area.
• Periodically check for leaks and watch water pressure as things thaw.

Water flow slowly returns, no burst, no dramajust a mental note to insulate that knee wall and add a small
temperature sensor in the space.

What they learned: Staying calm, working methodically, and respecting the “no open flame” rule
pays off. Frozen pipes don’t have to equal disaster if you act early and safely.

Big-picture takeaways from these experiences

• Know your home’s weak spots before winter: exterior walls, over-garage rooms, attics, crawlspaces.
• Find and label your main shut-off valve; show everyone in the household how to use it.
• Insulation and air sealing are boring… right up until the moment they save you thousands of dollars.
• In a real emergency, professional plumbers and restoration crews are worth their weight in gold.
• Most “frozen pipe horror stories” could have been avoided with small, early stepslike dripping faucets, leaving cabinet doors open, and keeping the heat up.

Put it all together and you get a very This Old House–style moral: good prep, solid basics, and a little
respect for physics go a long way. You don’t have to fear winteryou just have to outsmart it.