Cold-weather guide · Klamath Falls, OR

How to Prevent Frozen Pipes and What to Do If They Freeze

How to prevent frozen pipes comes down to three jobs: drain the outdoors, insulate and seal the cold spots, and keep water moving on the coldest nights. Here is each, plus what to do if one freezes.

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Cutaway of a home showing the plumbing systemWater main and sewer main under the street, a water heater in the garage, a toilet, a kitchen sink, drain lines and the sewer line. Numbered hotspots link to services.Water mainSewer mainWater heater1Drains2Leaks and pipes3Sewer line4Toilets and fixtures5
  1. Drain and insulateHoses off, hose bibs drained, cold runs wrapped.
  2. Drip on hard-freeze nightsA thin stream and open cabinet doors.
  3. Know your main shutoffFind it before a pipe splits.
The short answer

The short answer on how to prevent frozen pipes

At a glance
  • Drain the outdoor lines in fallRemove hoses, shut off inside, drain the hose bibs.
  • Insulate and sealFoam sleeves on exposed runs, caulk gaps where cold gets in.
  • Keep heat and movement on cold nightsOpen cabinets, drip a tap, keep the furnace on.
  • If one freezes, thaw gentlyOpen the tap, warm with a hair dryer, never a flame.
  • If one splits, shut off the mainThen call a plumber right away.
How a freeze happens

Why pipes freeze and why a frozen pipe bursts

Knowing the mechanism tells you which pipes are at risk and why a small trickle of water helps.

Ice is only half the story

Water expands as it turns to ice. That alone does not usually split a pipe. The damage comes from what happens next: ice forms a plug in one spot, and as more of the water freezes, the water trapped between the plug and a closed faucet has nowhere to go. Pressure climbs in that short stretch until the pipe wall gives, often some distance from the ice itself.

That is why a pipe can split in a place that looks fine and show nothing wrong until it thaws. The crack is there while the ice holds it closed, and the water pours out once the plug melts. Everything in this guide is built around two ideas: keep the pipe from reaching freezing, and give pressure a place to go if it does.

From cold to burst
  1. Cold reaches the pipe

    Unheated space, thin wall or open vent.

  2. Ice forms a plug

    Water stops moving past that point.

  3. Pressure builds

    Trapped water between plug and faucet.

  4. The pipe splits

    Often a lengthwise crack away from the ice.

  5. Water flows on thaw

    The leak shows when the ice melts.

How cold, how long

A brief dip below freezing rarely freezes a pipe that is inside a heated wall. What matters is how long a pipe stays cold and how exposed it is. Wind through a gap, a long run in an unheated space and a few hours of hard cold together are what do it. A mild freeze that lasts for days can do the same job as a short one that is very hard.

Pipes that carry moving water are harder to freeze than pipes with still water, which is why a slow drip from a tap is useful. Water that is moving also has a way out for any pressure that builds.

What raises the risk
  • Long cold stretchHours below freezing matter more than a single dip.
  • Wind on an exposed pipeAir leaks speed the heat loss.
  • Still waterPipes that are not being used freeze first.
  • Thin or missing insulationLess barrier between the pipe and the cold.
  • No heat in the spaceGarages, crawl spaces, attics, vacant rooms.
Where pipes are at risk

Where to look first when you want to prevent frozen pipes

Most freezes happen in a handful of places. Walk the house once and mark each one.

The usual spots, ranked by trouble

Look for any pipe that runs through a space the furnace does not heat. In practice that means pipes along exterior walls, runs in crawl spaces and unheated basements, lines in garages and attics, and the pipes behind kitchen and bath cabinets on outside walls. Outdoor faucets, called hose bibs or sillcocks, are the single most common failure point because they stick out into the cold.

Homes in the basin with a crawl space or a raised manufactured-home floor have long runs of supply pipe sitting in cold air under the house. Seasonal cabins and vacation homes are in a class of their own: without heat running, any water left in the lines is at risk for the whole season.

Pipes that freeze first
LocationWhy it freezesWhat to do
Outdoor hose bibSticks out; water sits in the stemRemove hose, shut off inside, drain; use a cover
Crawl space supply linesCold air and drafts under the floorSeal vents in the cold season, insulate pipes
Under a manufactured homePipes sit under the floor in open airSkirting, belly wrap, heat cable per its instructions
Garage and shop wallsDoor gaps, no heatInsulate, keep the door closed
Exterior-wall sink cabinetsThin wall; cabinet traps cold airOpen cabinet doors on cold nights
Attic supply or sprinkler linesAbove the insulation, in cold airInsulate over and around, drain if unused
Irrigation systemWater left in buried lines and backflow valveBlow out or drain before the first hard freeze
How to prevent frozen pipes in the usual trouble spots

Hidden spots that surprise people

A pipe can be in a heated room and still freeze. Look at where the pipe enters the house, where it passes through a rim joist, where a wall has a cold bay and where a bathroom fan or a dryer vent has a gap. A water heater closet on an outside wall, a washer hookup in a garage and a laundry sink in an unfinished corner are also common.

Look twice at these
  • Rim joist and sill areaGaps let in cold air along the pipes.
  • Wall bays behind a tubOften uninsulated on exterior walls.
  • Bathroom fan and dryer ventsOpen dampers draw cold air in.
  • Garage washer hookupHot and cold lines sit in unheated air.
  • The meter pit or main entryWhere the water line comes in from outside.
Before winter

How to prevent frozen pipes before the cold season starts

Autumn work takes an afternoon. A burst pipe in January takes weeks to repair.

A fall checklist in order

Do these in the first weeks of cooler weather, well before the first hard freeze. Disconnect and drain every garden hose, since a hose left on holds water into the bib and the pipe behind it. Shut off the inside valve to each outdoor faucet if it has one, open the outdoor faucet to drain, and leave it open until spring.

Then turn to the house. Seal gaps where pipes pass through walls and floors, close crawl space vents for the cold months if your home was built with them, and add insulation where pipes run through unheated areas. If you have an irrigation system, have it blown out or drained according to its instructions.

Fall prep
  1. Drain the outdoors

    Hoses off, bib valves closed inside, outdoor tap open to drain.

  2. Seal the gaps

    Foam or caulk where pipes pass through walls and floors.

  3. Insulate exposed pipe

    Sleeves on runs in crawl spaces, garages and attics.

  4. Handle the sprinklers

    Blow out or drain the irrigation system.

  5. Know your main shutoff

    Find it and test that it turns before you need it.

Know your shutoffs now, not later

In a freeze emergency every minute counts, and finding a stuck main valve in the dark with water spraying is the wrong time. Locate the main and each outdoor shutoff in the fall, and make sure the handles turn. Our guide to how to shut off the main water valve shows you how, and a valve that will not move or leaks at the stem is a repair for a plumber before winter.

It also helps to note where the meter is and where any heat cable controls or breakers live. If you rent, tell the landlord what you found and ask about the building’s shutoffs.

Find them in fall
ShutoffWhere to lookTest
Main water valveWhere the line enters, often a basement, utility closet or crawl spaceTurn it closed and open once
Hose bib interior valveOn the supply line just inside the wallTurn closed; open outdoor tap to drain
Water heater supply valveOn the cold inlet pipe at the heaterConfirm it turns
Irrigation shutoffNear the backflow assemblyClosed before draining
Shutoffs worth knowing
Insulation and heat

Insulating pipes and sealing the cold out

Two defenses work together: slow the heat loss from the pipe, and cut the cold air reaching it.

Choosing a defense for each pipe

Foam pipe sleeves are the simplest fix for exposed runs. They slow heat loss, they cost little in effort and they stay in place with tape or ties. Wrap right up to every elbow and fitting, and tape the seams. For pipes in an exterior wall, insulation in the wall cavity and sealed air gaps matter even more than the sleeve.

Heat cable, sometimes called heat tape, can protect a vulnerable run, such as a crawl space line. Use only a product made for pipes, follow the maker’s instructions to the letter, never overlap the cable and replace a damaged one. These products are a fire risk when misused, so unplug and stop using any cable with scorching or cracked insulation.

Pick the right tool
DefenseBest forWatch for
Foam pipe sleeveExposed runs in cold spacesGaps at elbows and valves
Wall and rim joist sealingPipes in exterior wallsAir leaks around penetrations
Heat cable made for pipesHard-to-insulate runsNever overlap; follow instructions exactly
Hose bib coversOutdoor faucetsCover helps; draining the line is better
Skirting or enclosureUnder raised homesKeep vents set for the season
Heated space nearbyPipes close to a warm roomDoes not help if the door stays shut
Ways to keep a pipe above freezing

Heat is the best insulation

No wrap stops a pipe from freezing if the cold lasts long enough, because insulation only slows the loss of heat. The strongest protection is warmth in the space itself. Keep the furnace running, keep the garage door closed, and let some house warmth reach pipes by opening cabinet doors on cold nights.

Check on the water heater too. A heater in an unheated garage or closet needs its pipes insulated, and a unit that fails in the middle of winter is a bad time for a repair. See water heater repair if yours is acting up before the cold season.

Warmth first
  • Thermostat steadyAvoid setting the heat low when away.
  • Cabinet doors open on cold nightsLets warm air reach pipes on exterior walls.
  • Garage door kept closedLimits cold air on shared walls.
  • Unused rooms kept above freezingCold rooms freeze pipes behind their walls.
  • Heat cable inspectedCheck it before each season.
During a freeze

What to do on a hard-freeze night to keep pipes from freezing

When the forecast turns very cold, a few small habits cover most of the risk.

Tonight’s checklist

Open the cabinet doors under sinks that sit on outside walls so warm air can reach the pipes. Let a thin stream of water run from at least one tap, ideally a tap on the farthest or coldest side of the house. A pencil-lead stream is enough: moving water is harder to freeze and relieves pressure.

Keep the heat on and set it no lower than about 55 degrees when you are out, a general rule of thumb. Close the garage door and any crawl space access. If a heat cable is installed, confirm it is on. Make a habit of checking the coldest tap in the morning: if it is a trickle or nothing, treat it as a possible freeze and act right away.

A cold-night routine
  1. Open the cabinets

    Warm air reaches pipes on outside walls.

  2. Drip one tap

    A thin stream keeps water moving.

  3. Keep the heat on

    Do not turn it down when you leave.

  4. Close the garage

    And seal crawl space access.

  5. Check the coldest tap

    In the morning, test it first.

Away from home in winter

A house that sits empty is the riskiest one. If you leave for days, keep the heat on at a steady setting, ask someone to look in daily and tell them where the main shutoff is. For a longer absence or a seasonal home, many people shut off the main, open the taps to drain the lines and drain the water heater, a job a plumber can do correctly.

If you do leave the water on and the heat running, a neighbor or friend who knows the shutoff matters more than any gadget. A house you check within a day is a much smaller risk than one nobody sees for weeks.

When you are away
PlanHowBest for
Heat on, someone checks dailySteady setting, spare key, shutoff shownShort trips
Main off, lines drainedClose main, open taps, drain the heaterLong absences, seasonal homes
Smart monitorTemperature and leak sensors with alertsAn extra layer, not a replacement
Pipes drained and winterizedDone by a plumberCabins and vacation homes
Leaving a house in winter
If pipes freeze

What to do if your pipes freeze, step by step

Move calmly. A frozen pipe that has not split can often be thawed without damage.

Thawing a frozen pipe safely

Signs of a frozen pipe: a tap that runs a trickle or nothing, frost on an exposed pipe, a bulge or crack, and sometimes a gurgling or whistle as water tries to pass. Start by opening the faucet served by the frozen line, so melting water has a place to go. Then find the frozen section, usually the coldest wall or space.

Warm it gently, starting at the faucet end and working back toward the ice. A hair dryer, a heating pad wrapped around the pipe or warm towels all work. Keep checking for leaks as ice melts. If the pipe is inside a wall, raise the room temperature and call a plumber instead of cutting into the wall.

Safe thawing
  1. Open the faucet

    Let melting water flow out.

  2. Find the frozen section

    Coldest wall, crawl space or garage.

  3. Warm gently

    Hair dryer, heating pad or warm towels.

  4. Work toward the ice

    Start at the tap end and move back.

  5. Check for leaks

    Shut off the main if water appears.

What never to use

A blowtorch, a propane or kerosene heater, a camp stove or any open flame can ignite framing, melt solder joints and scald you. A pipe that is hot to the touch can burst from steam. Never run an electric appliance while you stand in water. And never try to force a stuck valve or keep heating a pipe that has already split.

Do not do this

No flames, ever

Open flame near a pipe is a fire risk and can destroy a soldered joint. If a hair dryer does not work, stop and call. A plumber can thaw a pipe with equipment designed for the job.

If a pipe splits

A frozen pipe has burst: shut off the water and get help

A split pipe is an emergency. The water often starts flowing as the ice melts.

The first ten minutes

Close the main water valve at once. Open the taps to drain the lines, and, if water is near electrical outlets or the panel, switch off power only if you can reach the breaker without standing in water. Move belongings out of the wet area and call a plumber. Our what to do when a pipe bursts guide takes you through the sequence in more detail, and burst pipe repair explains the repair.

Take photos and short video of the damage before cleanup. If you plan to claim any loss, our guide on whether homeowners insurance covers plumbing leaks and burst pipes sets out what to ask your insurer. For help right now, the emergency plumber line is open 24/7.

Burst pipe first steps
  1. Main valve off

    Stops the flow at its source.

  2. Drain the lines

    Open taps to relieve pressure.

  3. Mind the electrics

    Stay out of standing water near outlets.

  4. Move belongings

    Get contents away from the wet area.

  5. Call and document

    Plumber first, photos before cleanup.

After the thaw

Even if nothing leaked while the pipe was frozen, check once everything has thawed. Walk the house, look at ceilings and walls, listen for running water and watch the meter with everything off. A hairline crack may weep only a little but can wet insulation and framing for weeks. Our leak detection service finds the hidden ones, and our how to find a water leak in your house guide covers the meter test.

After a freeze
  • Meter with everything offAny movement means a leak.
  • Ceilings and wall cornersStains and sags show hidden water.
  • Water pressure at every tapA split can cut flow.
  • Crawl space and garageLook at the cold runs.
  • Water heater areaCheck supply and relief pipes.
Fixing the weak spots

Permanent fixes that make frozen pipes much less likely

If one spot freezes year after year, the cure is a change to the pipe or the space, not more wrapping.

Rerouting, replacing and upgrading

A pipe that freezes every cold season is in the wrong place. A plumber can move a supply line out of an exterior wall, replace an old hose bib with a frost-free model that shuts the water off inside the heated wall, or run new pipe through a warmer path. See pipe repair for these fixes and repiping if a whole house has too many weak runs.

Some repairs are about air and warmth, not plumbing: sealing a rim joist, insulating a crawl space wall or fixing a garage door seal can be as effective as any pipe work. Old, corroded pipe also splits more easily, so if you have seen rust or pinhole leaks, our guide on signs of corroded pipes is worth a look.

Fix the cause
Chronic problemPermanent fix
Hose bib freezes every yearFrost-free sillcock installed
Kitchen sink on an exterior wallReroute supply or add wall insulation
Crawl space line keeps freezingSeal, insulate or reroute the run
Garage supply lineInsulate, heat the space or move the line
Old brittle pipe splits easilyReplace the section or the system
From wrap to real fix

What moves the price

No page can price a pipe job it has not seen. Cost follows access, material, pipe length, the number of runs involved and any wall or floor repair after the work. Ask about pricing when you call and say where the pipe is and how many times it has frozen.

Tell us this on the call
  • Where the pipe runsOpen crawl space or finished wall.
  • How often it freezesA pattern points to rerouting.
  • Pipe material and ageOld pipe may need more work.
  • Is it already splitRepair after damage costs more than prevention.
When to call

Frozen pipe signs that call for a plumber

Some freezes you can thaw yourself. These you should not.

  1. Water is leaking or spraying

    Shut off the main and call. A split pipe cannot wait.

  2. The frozen pipe is inside a wall or under a slab

    Opening a wall or heating blind risks damage.

  3. A pipe is bulging or cracked

    Ice has already stressed the wall of the pipe.

  4. Thawing is not working

    Equipment made for the job beats guesswork.

Questions

Questions about how to prevent frozen pipes

How to prevent frozen pipes when a hard freeze is forecast?

Open the cabinet doors under sinks on outside walls, let a thin stream run from a tap on the coldest side of the house, keep the furnace on and the garage door closed. Disconnect and drain hoses and outdoor faucets before the cold arrives.

Should I leave my faucets dripping?

On a hard-freeze night, yes, on the coldest taps. Moving water is harder to freeze, and a trickle relieves pressure if ice forms. Open both hot and cold on a mixing tap if you can. Turn them off when the weather warms.

What temperature should I keep my house at to avoid frozen pipes?

A common rule of thumb is no lower than about 55 degrees when you are away, and your normal setting when you are home. The right level also depends on how much cold reaches your pipes, so a house with exposed runs may need more.

How do I thaw a frozen pipe safely?

Open the faucet, then warm the pipe slowly with a hair dryer, heating pad or warm towels, starting near the faucet. Never use a torch, a propane heater or any open flame. If you cannot find the frozen section, or it is in a wall, call a plumber.

Will my pipes burst if they freeze?

Not always. Many freeze without splitting, especially if you thaw them gently. But the risk is real: the pipe can crack where pressure builds, and the crack may only show when the ice melts. Check carefully after a thaw.

Is it enough to wrap pipes in insulation?

It helps, but insulation only slows heat loss. A pipe in a cold space with no heat can still freeze in a long cold spell. Combine insulation with sealing air gaps, warming the space and keeping water moving on the coldest nights.

What should I do with outdoor faucets before winter?

Remove hoses, close the inside shutoff valve if there is one, open the outdoor faucet to drain, and leave it open. A frost-free faucet helps, but it still needs its hose removed or it can hold water and freeze.

Does homeowners insurance cover frozen pipes?

Policies differ, and coverage often depends on the cause and the steps you took. Read your own policy and ask your insurer. Our guide on insurance for plumbing leaks and burst pipes lists the questions to ask.

How much does it cost to fix a burst frozen pipe?

It depends on where the pipe is, how much of it must be replaced, the material and the repair to walls or floors afterward. Ask about pricing when you call and describe where the split is.

Can I get a plumber on a freezing night?

Yes. The line is open 24/7 and same-day service is available. If water is flowing, close the main first, then call. Our burst pipe repair page explains what happens next.

Pipe frozen or split? Call now.

Shut off the main if water is flowing, then call. Open 24/7, with same-day service available. Ask about pricing when you call.

Call now, 24/7(541) 407-8900