How To Defrost Pipes

You wake up. Your toes recoil the instant they hit the floor. Your breath forms stalactites in the air. You go to wash your face, and squeak squeak, the knobs turn but no water comes out. Damnit. The pipes are frozen. How do you get the water flowing again?

First check to make sure the pipes aren’t cracked, because then you need to replace them and not just warm them up. Assuming they’re not cracked, open up all the faucets and showers. Then you can try the following:

  • Run a hairdryer over the frozen section.
  • Boil some water (you do have an emergency supply of several gallons of water, right?), wrap the pipe in a towel and pour boiling water of the section of pipe.
  • Put a space heater near the pipes
  • Put an incandescent light near the pipes
  • Pour salt water down the drain
  • Wrap the pipe in a heating pad and turn it on.
  • Wrap the pipes in electrical pipe heating tape.
  • Run a blowtorch back and forth over the pipes. Obviously don’t do this with PVC or other plastic pipes.
  • Pour boiling water down the drain.

To find the frozen section of the pipes, bang along its length until you hear a part that sounds different. This piece of the pipe will probably be located wherever the cold water pipe runs through the coldest part of the house.

Of course, prevention is the best cure. Make sure to properly insulate your pipes and walls. And if you know it’s suddenly going to get super-cold, you can ward off your pipes getting frozen if you leave your pipes running just a trickle the night before the cold weather hits.

What techniques do you use to thaw your pipes?

How to Thaw Frozen Pipes [eHow]

Comments

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  1. Mr. Fix-It says: "Canadian Bacon is best bacon!" says:

    Uhm… you suggested ‘hairdryer’ twice.

    • jamster says:

      Thats because its actually a complicated order of things you need to do.

      Hairdryer, water over pipes, hairdryer again, space heater, heating pad, heating tape, blowtorch the pad and tape off the pipe then pour water down a drain (which will somehow unfreeze the water pipes).

    • Keep talking...I'm listening says:

      One for each hand…

  2. Darrone says:

    Is this common? I’ve never heard of pipes freezing without bursting?

    • gparlett says:

      Yeah, it happened to us several times when i was a kid. My dad would use a candle to unfreeze the pipes. I never knew how he found the frozen section though.

      • MrEvil says:

        I bet your dad probably new where the pipes were least likely to be frozen and just used thermal transfer to find the ice for him.

    • phil says:

      Typically, pipes will freeze enough to prevent water flow – just before bursting. Much of this behavior depends on pipe material. I’ve seen frozen water split and peel back the sides of copper pipe – even though I thought that pipe was empty at the time. I’ve also seen plastic pipe freeze solid, while under water pressure – and thaw out with no apparent damage.

      I don’t personally have experience with frozen PVC or CPVC pressurized supply lines. I’m told PEX can take a surprising amount of abuse, including freezing – though fittings are another story.

      A word about blowtorches: I hear about house fires caused by this behavior every year. I’d find another approach, just to skip the possibility of reading your name in the next day’s newspaper…

    • redskull says:

      Happens in my house every time the temperature dips below 20º. I know, I’ve been lucky that they just freeze and don’t burst. But it is possible.

  3. anker says:

    dangit!
    I haven’t had cold water in my kitchen sink for two days. Plenty of hot water has been put in from scalding my hands doing dishes, didn’t thaw a thing.

    How do I find which section of pipe it is? (I’m serious, I’ve never had to do this before)

    • Cheap Sniveler: Sponsored by JustAnswer.comâ„¢ says:

      Look for a place where the cold water pipe goes through the coldest, unheated part of the house.

      • anker says:

        My sink backs right up to the outside with no wind protection, that’s got to be the spot.
        Next summer I can get back there and somehow insulate it all a little better.
        This house was built in 1850 with little upgrade since then if that tells you what I’m up against.

    • rushevents says:

      Mine have frozen because they were close to a crawl space door and cold wind could freeze them. Look for uninsulated pipes near external walls and crawl spaces(under the house) or attics over the ceiling).

      Since your hot water pipe is not frozen try tracing it back to see if there is a section of the cold water pipe (usually next to the hot) where it is not insulated or next to a cold external wall. That would be a good place to start.

      Time is of the essence – if the freeze is bad enough it might expand far enough to burst the pipe. the sooner you get a hairdryer on it the better.

  4. Tim says:

    The other thing to watch out for is that since water expands when it freezes, it could actually break your pipes. If it become a problem often, your best bet is probably keeping heating tape on them at all times.

  5. utahgamer says:

    Trying “any combination of the following” seems rather ill advised for several combinations from that list, many of which would lead to a quite flashy electrical death.

  6. mkuch90 says:

    My landlord makes us keep the temp above 65 so this doesn’t happen. 5 bucks a month extra is worth not having to pay several thousand for burst pipes.

    • Necoras says:

      We keep the house at a reasonable temperature, but there are pipes running through the attic and then along external walls to outdoor faucets that have frozen before.

  7. ellmar says:

    The blowtorch method is a very effective way to burn your house down!

  8. Jason says:

    I was told never to pour boiling water on metal pipes due to the shock it causes going from freezing to boiling with rapidly expands the metal and bursts seems and solder.

  9. wsam1 says:

    That “hairdryer” shown in the picture is actually an industrial-grade heat gun. Temperatures of 380+ F are enough to melt that PVC. I’d like to see a women try to dry her hair with that.

  10. suburbancowboy says:

    What would pouring boiling water down the drain do? Aren’t the drain pipes separate from the supply pipes? If my supply pipes aren’t frozen, then I should be able to get hot water out, which would in turn start to melt any frozen water that might be in the drain pipes, which shouldn’t have much any water in them anyway, if they are draining correctly.
    But I’m not a plumber, so I could be totally off base here.

    • Banned in DC says:

      Depending on the location of the drain, the water in the drain trap could possibly freeze too, leading to drainage backups.

  11. curiositykt says:

    Er. The blow torch option causes hundreds of fires every year in New England. Generally they put the torch too close to something flammable, and it smolders for a few hours and then the house burns down. It’s a very bad idea.

  12. Nighthawke says:

    First off, lack of foresight in checking the weather to see when it would get below zero in your basement. Second, not buying 25 bucks worth of foam pipe insulation, 100 bucks of electric heating tape and putting it all in place BEFORE the first cold front of the season rolls in.
    Third, investing in improved insulation of your basement or attic to prevent freezups and lower your utility bills, to boot!

    Shoulda, Coulda, Woulda. Get to budgeting for next years deep freeze so you will not be paying a plumber a cool 500 or more to fix your mistakes.

    • FrugalFreak says:

      I just shut off my water and drain my pipes if it gets below 25. Safe way to be proactive. A day without water is a whole lot cheaper than couple hours plumbing repair bill.

  13. Cheap Sniveler: Sponsored by JustAnswer.comâ„¢ says:

    Damn. I spent 6 hours under a trailer after midnight thawing pipes, and installing new heat tape because the previous owner never took care of anything.

    I suggest PREVENTION as the solution: Put heat tapes on vulnerable areas BEFORE it gets cold, and test them every fall. $30 for a heat tape beats 6 hours in the freezing cold lying on the ground with a flashlight.

    • RadarOReally has got the Post-Vacation Blues says:

      Everyone who’s saying prevention is the best solution is, of course, right. But things happen, even to perfect people like you guys. Basement window breaks, hatch blows away, people just plain forget to plug in the heating tape, whatever.

      I agree that people who live in the northeast should be proactive, but it’s not at all productive to ridicule people who make a mistake, or have an unforeseen circumstance.

      • Cheap Sniveler: Sponsored by JustAnswer.comâ„¢ says:

        No ridicule intended. Just pointing out, an ounce of prevention, etc.

  14. shepd says:

    I live in the frozen north, and burst pipes are ALWAYS the fault of the homeowner being way too cheap with their heating, or someone putting pipes in the wrong places. I have never, ever, ever had a pipe even come close to bursting from being frozen (I have had a pipe burst because the landlord was too cheap to ever replace the host going to the washing machine, but that’s not due to freezing, that’s due to it being 20+ years old and made of rubber).

    With people being too cheap on heating, guess what, there’s a reason most thermostats won’t go below 10-15 C! Because below that and the cold areas of the home hit freezing temperatures!

    And then there’s either idiot handymen or idiot builders who put pipes in cold spaces (eg: in the attic without insulation covering them, although, honestly, in the attic at all is stupid). NO! DUMB! Pipes go in the walls and under your floors. I suppose if you’re in a place without basements, it might be a little more complicated than that, but that sort of structure is really rare about here.

    • terrillja says:

      Actually, we had a radiant heat pipe freeze and burst because it was a sunny day and the house was warm except for where one loop of the pipe was. So because the house was warm enough, the warm water wasn’t circulating and it froze. It would have helped to insulated it somewhat better as it was a loop against an outside wall, but being cheap on heating was not part of the problem at all.

      • shepd says:

        If the pipe were on the inside, it wouldn’t have burst. Which is what I mean by being cheap on heating. Some broke people turn their heating off in the winter and just load up on blankets. That means all the pipes on the inside/insulation protected pipes freeze anyways because the inside of the house is cold enough to let them. :-)

        • terrillja says:

          Outside wall as in the loop between the wall and the floor joist next to the wall. Radiant heat doesn’t work by heating your outside walls. It was inside the house. My point is that temperature in the house is not the same thing as in between the floors. It isn’t a matter of being cheap. Sometimes there are just conditions that are unforeseen.

    • evnmorlo says:

      It’s usually do to a defect with the house. Most houses are built like glorified shacks.

    • Nigerian prince looking for business partner says:

      Running pipes in an old home can be a challenge, especially if it’s built on a slab and has no studs on exterior walls.

      I have a very narrow crawlspace and it takes a lot of creativity when running pipe and is especially rough when trying to keep the inspector happy.

  15. Fjord says:

    Before I installed the new furnace in my house I had to deal with this every year. I have to say that I have replaced the system in the house twice, it is PVC and if a leak springs I need no more than 20 minutes. PVC pipes are like Legos if you get the hang of it.

  16. steam says:

    I would not put a Heat Gun, as shown in the photo, in the clean-out plug. The best method is heat tape, or slowly heating the wall cavity or room the pipe is located in. It’s also a good idea to shut-off the main valve to preclude a flood in case a pipe has cracked.

    Heat Guns can reach temperatures that can cause combustion, hair dryers do have such high temperatures. In any case slow heating is the best idea; stay away from flames and extreme temperatures. Never use flames in a wall cavity or a space were a hidden smoldering fire could be started.

  17. MrEvil says:

    I haven’t had fresh supply lines freeze on me. But last winter I had a slug of ice freeze in the drain from my washing machine. Luckily only a small amount of water got pumped out onto the floor before I stopped the machine. After a day and a half of waiting for the drain to thaw naturally, I heated up a kettle of water (not boiling, merely tea hot) and poured it down the drain with a funnel at the warmest point of the day. That’ll teach me to wash clothes when it’s 0 degrees outside.

  18. Cheap Sniveler: Sponsored by JustAnswer.comâ„¢ says:

    If you live in an area that rarely gets cold enough to freeze, but occasionally the temps drop below freezing, you can prevent the pipes from freezing by keeping a trickle of water flowing through the faucet. But seriously, this is a stop-gap measure. When the temps rise again, get some heat tape on those vulnerable pipes!

    • Kate says:

      I was wondering if anyone had suggested this. This is what we used to do in an old rental house my mother owned, just set the water to a slight trickle, running water keeps it from freezing.

  19. Mr. Fix-It says: "Canadian Bacon is best bacon!" says:

    How I’ve always found the frozen section of pipe is you knock on the pipe with the side of your wrench, or whatever tool you happen to have handy.

    The plumbing sounds different when you knock on a frozen section as opposed to an unfrozen part. But then, I’ve had metal plumbing for the longest time, so my method might not work on say, PVC plumbing.

  20. aloria says:

    I use this thing called “insulation” in combination with this thing called a “thermostat,” they both work together to keep the pipes warm enough so that they don’t freeze.

  21. He says:

    If you know this is a sporadic problem (ie not enough to require the installation of the heated tape stuff), you can also put an incandescent light directly next to the pipe the night before. Like one of those automotive work lights that has a hook to hang it on.

    • Mr. Fix-It says: "Canadian Bacon is best bacon!" says:

      We call them ‘trouble lights’ – as in, “if you need it, you’re in trouble!” ;P

    • Cheap Sniveler: Sponsored by JustAnswer.comâ„¢ says:

      Note: incandescent light. Not CFL or LED.

      This trick will only work until our government makes incandescent lights illegal. And by the same law, your kid’s “Easy Bake Oven”

  22. kc2idf says:

    “(you do have an emergency supply of several gallons of water, right?)”

    There is snow on the ground.

    • GuyGuidoEyesSteveDaveâ„¢ says:

      There is also water in your toilet tank, and you would also have a good supply in your hot water heater.

    • catastrophegirl chooses not to fly says:

      not necessarily. the coldest days this winter where i am have not been the snowy days. the snow has actually been on days that are about 20 degrees warmer. and around here it only sticks for a week tops. so while it may have been 15 degrees out saturday night, it was bone dry

  23. Glaurung_quena says:

    “Run a blowtorch back and forth over the pipes. Obviously don’t do this with PVC or other plastic pipes.”

    Only if you’re stupid – someone tried this in an apartment complex I lived in when I was young, and burnt down the entire building (about five apartments, fortunately not including ours)

  24. TheMonkeyKing says:

    I read the headlines as, “How to Defrost Pies.”

    I must need more sleep.

  25. lockdog says:

    I used to have this problem every winter once temperatures dipped into the low teens. Most line would open in the morning just by opening and shutting the valves or running the hot water through an adjacent line. Severely frozen lines (like the washing machine) would stay that week until we had temps well into the 30s overnight. Pip insulation helped some, heat tape did some more, but the thing that really made a difference was extra insulation in the attic (even though pipes are in crawl space) and replacing my windows. It was -2 F the other night, and the only effect was a slightly slushy supply to the laundry room, and it cleared right out once the valve was opened. Luckily, I’ve never had a burst pipe from all this freezing, but from the looks of old repairs, previous homeowners did.

  26. Loias supports harsher punishments against corporations says:

    Or, you know, keep your home above 55 degrees and wrap any exterior piping.

  27. Nigerian prince looking for business partner says:

    I have an uninsulated craw space and have had recurring problems with frozen pipes. I’ve always used the hair dryer method to thaw them out.

    Like others have suggested, prevention is the best option. I’ve found that a single incandescent light bulb in the craw space is enough to keep them from freezing and is cheaper than running the heat tape for every pipe under the house. An even easier solution is to just let faucets drip very slightly.

  28. INDBRD says:

    What is pouring water down the drain going to do… chances are you drain isn’t frozen as their is little ‘standing’ water in it….

    • Nigerian prince looking for business partner says:

      I’ve seen drain traps freeze when in cabinets attached to exterior walls, especially in older homes which are just plaster-on-brick with no insulation.

  29. dulcinea47 says:

    You can also pour salt down the drain to help with the melting. One of the worst landlords I ever had, who didn’t really give a crap that my pipers were frozen, gave me that tip. It actually works if things aren’t frozen too solid.

  30. veritybrown says:

    One thing NOT to do: leave the taps in the “open” position and go away for the weekend. No one could be that dumb, right? Wrong–my best friend’s ex did exactly that a couple of weeks ago. The supply pipes thawed before the drain pipe did, and my best friend’s teenage daughters came home to find all their stuff standing in an inch or more of water throughout the house.

    So let’s add this little piece of advice: DO NOT LEAVE FROZEN PIPES UNATTENDED! At some point, they *will* thaw. Then you might have a broken (and now leaking) pipe to deal with. Believe me, you will want to be around to deal with that situation, not wait to discover it days later!

  31. GreatWhiteNorth says:

    For drain pipes (could be copper, cast iron or plastic) consider dumping hot (not boiling) salt water down the drain. Get as much salt dissolved as possible. Be careful you don’t use so much water that you are creating a bigger problem if the drain doesn’t open.

    As for water supply pipes (could be copper, or various plastics) as has been suggested prevention is best by insulating and installing heat tape before it is needed. Thaw slowly and know where the main water shut off is prior to starting so that if the pipe did burst during freezing you can minimize damage. It is also a good idea if you have the tap open when thawing as the water that starts flowing will help thaw the ice left in the pipe. Heat source should be safe, use caution with all flames including having a source of fresh air and use caution with electricity as you may have water leaks develop.

  32. Felux says:

    Oh how ironic. I woke up to frozen pipes in my house this morning. There is a small unheated section of my basement where the water pipe entrance is. I just stuck a space heater in there to work its magic. Hopefully things will be back to normal in an couple hours.

  33. teraax says:

    Do not use the blow torch technique. Besides the obvious “burn your house down” problem, the rapid heating of the pipe can cause the water to boil and then refreeze further down the pipe. This can add excess stress which can clead to pipes bursting.

    Leaving a trickle of water is a good preventitive method as well as the heat tape (if you have exposed pipes, do not use heat tape inside insulated walls, even if you have an “access panel” built in).

    If they are frozen, the hair dryer, light bulb, and the hot water soaked towel all work well in most cases.

    For really stubborn situations call around to electricians in the area (not many plumbers keep this equipment on hand anymore), see if anyone has an arc welder with extended leads on it. They can connect one lead to the pipe near the water meter and another on and out door faucet. Then you can open up several faucets and run a current through the pipe. The entire pipe will heat up evenly. IMPORTANT: This should only be done by a professional and make sure your house eletrical panel is not grounded to your water line if it is you will have to shut off the power to the house and disconnect the ground before running the current.

  34. scoosdad says:

    When I moved in 15 years ago I discovered that the pipes to the kitchen sink ran through the ceiling of my garage and were constantly freezing up if I didn’t also heat the garage. Typical thing you see on Mike Holmes’ TV program on HGTV. But the hot air duct up to the kitchen also ran alongside the same water pipes to a vent under the kitchen sink. We got creative– we opened up the hot air duct where it entered the space coming through the garage wall beneath the floor, lined the cavity with sheets of foam insulation, and sealed the ends and over the whole thing with expanding foam insulation, some caulking, and reinstalled drywall back over it on the garage ceiling, basically building an insulated air duct that surrounds the water pipes. Opened up the floor under the sink into the heated cavity to let the hot air come out through its usual vent under the sink and voila– no more frozen pipes. So long as the heat in the house is running, the pipes down there have never frozen.

    Course now I have to run the cold water a long time during the heating season to actually get cold water. Most of the time it runs very warm at first, but that tells me it’s working. The neighbors in adjoining houses built the same way have come by to study my method and a few have copied it. I’ve since replaced my garage door with a heavily insulated and better sealed unit, so it’s probably not necessary now, and one of these days I want to have a contractor come and properly spray-foam insulate the garage and the floor above it. I can just see Mike Holmes looking at what we did and shaking his head.

  35. JohnJ says:

    thisoldhouse.com has a How to Prevent Frozen Pipes video:

    http://www.thisoldhouse.com/toh/video/0,,20045368,00.html

  36. damageddude says:

    Our pipes to/from the hot water heater froze our first really cold winter in our house (still had cold water). The hot water heater is in an unheated utility room entered from the outside, near the furnace (no basement), which does help keep them from really freezing. The rest of the pipes are in the floor of the house (which was a pain when one leaked — had to chop up the wood floor, yay insurance). I called a plumber as I was new to home ownership at the time (had always lived in apartments) and didn’t have a clue what to do.

    After that I bought some cheap foam at Home Depot and covered the pipes against the wall (those were the ones that froze) to insulate them and haven’t had a problem since. I also leave the hot water dripping in the bathroom which is probably overkill as we’ve had similar cold nights over the years where I forgot to open the hot water tap.

  37. brokenworld says:

    As someone who works at a plumbing supply company let me make a suggestion: You SHOULDN’T call up the company screaming that you’re going to sue us because our ‘faulty’ pipes froze in below zero weather.

    Please don’t.

  38. chbrules says:

    I live in so-cal. What is ice?

    • scoosdad says:

      It’s the stuff that when melts with dirt, turns into mud. You DO know mud in California, don’t you?

  39. FrugalFreak says:

    UH, FIRST thing to do is turn off water at main to reduce pressure.

  40. FrankReality says:

    After we bought our old farmhouse, we had a lot of problems with freezing pipes running to the kitchen. That first winter, we drained them every night. The pipes ran through an unheated crawl space. When we remodeled the kitchen, we found a heat tape which had burned out, but we rerouted the water lines down an interior wall from the bathroom upstairs. That helped a lot, but we still had some occasional freezing when the wind came howling from the north. There’s nothing like – 30 F temps with a 30 MPH NW wind to freeze pipes.

    I used every one of those tricks to thaw pipes and then some – hair blower, propane torch, heat gun, heat tapes, disassembling traps, etc. Oddly enough, we never had a pipe break or split.

    Since the kitchen was always cold, we added another forced air run through the crawl space and rising up under the cabinet for the kitchen sink. We then ran the plumbing right next to the new heat run. We also did some insulation around the foundation and had a few holes punched in the heat run to keep the crawl space warm enough that the water lines couldn’t freeze.

    The other area of freezing is our well pit. The pit is around 6 x 6 x 6 foot concrete box. The top of the box is just above ground, the rest is in the ground. Inside the pit is the well head, pressure gauge and switch, the well controller, pressure tank, a light fixture, a sump pump and pipes/shutoffs to the buildlings. When it gets really cold – 30 F, the pressure switch can freeze.

    Because the environment in there is extremely wet (water condenses on the ceiling), the old farmhouse heaters with motors tended to rust up in a year or two. Second, you could never dial them down do a just above freezing temperature.

    When I rewired everything in the pit, I put in GFCIs, a waterproof light fixture, a waterproof switch for the light, a waterproof receptacle, a sealed thermostat that triggers at 35 F and a pair of heat lamps. No more freezing and no more heaters to rust up. The dual lamps are redundant in case one burns out. The last touch was to have a switch for the heat lamps that I can reach from the pit entry cover so I don’t have to climb down into the pit just to turn them on.

    No freeze anyhere since. Let’s just say prevention sure as heck beats thawing and replacing pipe.

  41. Mackinstyle1 says:

    Wait, this is a problem in the modern world?

  42. sp00nix says:

    my pipes run along or near the hot water pipes for the heat. I guess thats a win for me.

  43. abz_zeus says:

    Best idea for drain is use hot brine, you need to be careful it will be over 100C (220+F)

    Fill pan with water and heat, dissolve as much salt as possible literally till you see salt lying at the bottom now carefully pour into drain.

    Heat melts ice, heat also means more salt, more salt also means hotter. And salt also melts the ice so you get a steady dissolving of the ice plug