How to Avoid and Thaw Frozen Pipes Safely

Every winter many people in the colder climates face the danger of frozen pipes. Naturally construction techniques should be used to minimize the possibility of frozen pipes such as not running pipes in outside walls, and through unheated areas, but, even then there is the possibility of a draft through an area that was not sealed or, insulated properly. Quite often people do things like leave a garage door open for an extended period of time, not thinking about the fact that there is a master bath above the garage with pipes in the garage ceiling and walls.

What Happens When Water In A Pipe Freezes?

When water freezes, it freezes in a hexagonal form that takes more space than in its liquid state, increasing its volume by about 9%. When a pipe freezes with two separate ice plugs the water in between the two ice plugs can generate pressures far higher than any pipe can contain, unless the pipe can stretch without breaking and accommodate this 9 % increase in volume. Water cannot be compressed and the freezing process may generate pressures as high as 40,000 PSI. When a pipe freezes fast action is necessary to prevent the freezing pipes from bursting. Almost all pipes used for water supply in the home are highly susceptible to bursting with the exception of PEX tubing. PEX is a cross linked polyethylene that has the ability to stretch without damage and contract to it’s original state when the expanding force is removed in many cases, this ability lessens the danger of PEX bursting. Other pipes such as copper, CPVC, brass, and galvanized steel cannot expand without splitting.

How To Thaw Frozen Pipes

As soon as pipe freezing is recognized by fixtures suddenly losing their water supply, immediate action is required. Hot water supplies often freeze first due to a phenomenon known as the “Mpemba effect.” Turn up the heat, leave the affected faucets open, open doors to areas such as closets, and cabinets, to allow the heat to get into the areas where the pipes are frozen. In unheated areas such as garages and crawlspaces space heaters may be used with caution. If you know the exact location of the freeze a hair dryer is a good way to warm the pipe. Warming the area of the ice plug is the only way to thaw plastic pipes. Every year many people make the mistake of using a torch to attempt to thaw pipes. Many fires are caused by this unsafe act. Do not under any circumstances use a torch to thaw frozen pipes.

Pipe Thawing Machines

If you have metal pipes such as copper, brass, or, galvanized steel you should immediately call a plumber and look for one that has an electric pipe thawing machine. If the plumber says that he doesn’t have a pipe thawing machine but can do it with his torch say no thanks. The Ridge Tool Company makes two excellent pipe thawing machines the Ridgid model KT-190 & KT-200, General Pipe Cleaners also makes 3 excellent thawing machines, the General Hot-Shot HS-320, HS-400, and the CHS-300 which is CSA Approved for use in Canada. These machines plug into a regular 120 volt receptacle and lower the voltage very low while increasing the amperage. Lowering the voltage reduces the chances of arcing virtually eliminating the danger of fire and increasing the amperage gives it the ability to produce heat when it flows through a metal pipe. These machines may thaw metal pipes up to 1 ½” in diameter without knowing the exact location of the freeze or having access to it. They will even thaw underground metal water service lines. The plumber merely has to connect the cables to the pipe on each side of the frozen section of the pipe and allow the electrical current to flow through the pipe until the ice melts. This is by far the fastest and safest way to thaw metal pipes.

Some people have attempted to use electric welders to thaw pipes. The amperage from an electric welder is certainly high enough to get the pipe warm and thaw the pipe however, unlike the pipe thawing machines electric welders provide a much higher voltage which can allow arcing to occur. Frequently when copper pipes freeze solder joints are pushed apart. If this has occurred in your home and a welder is used arcing can occur causing a fire, because of this electric welders are not recommended for thawing pipes.

How To Prevent Frozen Pipes

When you recognize that a specific area of your home has a freezing problem you should talk to the plumber about what steps can be taken to eliminate the freezing problem. Sealing the area that froze from drafts and insulating may help. Sometimes the pipes may need rerouting through safer areas. In open areas a good quality electric heat tape such as Frostex properly installed may be a good prevention measure.

What Not To Do With Frozen Pipes

One thing to avoid is the old myth of leaving the faucet running slowly to prevent the pipe from freezing. Not only is this a waste of water but it may cause a drain pipe to freeze. Frozen drains are by far the most difficult and expensive pipes to thaw. Most drains are larger than the capacity of electric pipe thawing machines and also many are constructed of materials that do not conduct electricity. The best method of thawing a frozen drain is to use a high pressure water jetter which is an expensive operation.

You should also check the plumbing fixtures in your home before the winter season to fix or, replace any dripping faucets or, leaking toilets. Drain lines should always be pitched so they drain dry when not in use. Normal use has water running through in sufficient volume and velocity that it does not cool enough to freeze while in the line. When there is a dripping faucet, leaking toilet or, other low flow into the drain there may not be sufficient volume to prevent it from freezing in your drain line. Drains that are in poor condition where they hold water in bellies or, sags are also susceptible to freezing if they are located in a cold area or above the frost line in the ground.

Above all Never Use A Torch To Thaw Frozen Pipes! You will surely get the pipes to thaw, but once the fire department leaves they will freeze again! Every year 5,580 fires in the US amounting to $208,000,000 are attributed to the use of torches, burners, and soldering equipment. Many of them involve pipe thawing operations!

Your home is no different than your car. As the cold weather approaches make sure that you home is in good shape and ready for the cold season. When problems occur, respond to them quickly and make sure that you don’t wait to call a good plumber when you run into problems such as frozen pipes.

Posted in How To Plumbing Tips, Plumbing Health and Safety, Plumbing Tools Tagged with: , , , , , , , , , , , , , , , , , , , , , , ,
17 comments on “How to Avoid and Thaw Frozen Pipes Safely
  1. Ruby says:

    I have frozen pipes but I can not located where it’s frozen from since it’s covered wid dry wall. The temperature been low for 2 days around 15-20 degrees outside n we bought n placed 2 heaters in the basement hoping it would help n left it on for whole night n I just checked the temperature has been 63 inside wid the heaters but there is still no water. Without water my heating system will not work either. Can there be any other problem?

  2. Sven says:

    Hello, It was -45 c. last week here at my place, I live in a double-wide trailer and my pipes froze last week. I have a crawlspace and have heat tape around the pipes the last few days it has been +5 during the day and 0 at night, the crawlspace is warm and I cannot see anymore areas that could be keeping the pipes frozen.

    My pressure tank is on 0 p.s.i and have no water still, my question is can I fill up my pressure tank to the correct p.s.i without having to worry if there may be still a frozen spot? Could the pipes burst? I am on a well with a submersible pump and my stepdad normally took care of these things but he passed on last year without passing info on about certain household problems. I believe in the past he just hooked up the air compressor to the tank and when he hit 30-40 p.s.i the water would run. I currently have the pump turned off and the gate valve to the pressure tank closed. any advice would be great, The pressure tank is an 85 lb John Wood in case you need that info.

    Thank you hope to hear from you soon


    • Redwood says:

      Hi Sven,
      Being in the US I had to convert the -49C to see just how cold that was. WOW! -49F That’s Cold! It’s good to hear that you at back up to just freezing at night and slightly above during the day that will definitely help. Hopefully you have a decent amount of snow cover to the frost didn’t extend too deep into the ground and freeze the line in from the well.

      I assume the valve you are talking about is between the house plumbing, and the well pump system including the pressure tank, pressure switch, and pump. As long as that is the case and it is not a valve that would isolate the pump from the pressure switch and tank, I would turn the pump on and see if it builds pressure. Hopefully it does. If it doesn’t, then turn it back off because that would indicate either the pump is not working or, the line between the pump and the tank has frozen. If the line is frozen then damage to the pump and pipes between the well and house could result. At that point it would probably be best to call in someone that works on well pumps to get it fixed quickly.

      If the pressure does build when you turn the pump on then you can open the valve and allow water to go on to the house plumbing and check for any additional leaks. There is no need to worry about the plumbing in the house bursting from you turning the water back on. The pipes are either already burst from freezing or, not. Hopefully you have found and repaired all the burst pipes and there are no additional leaks to repair. If you do have additional leaks then turn off the valve again and the pump can be left turned on, it will shut off on its own once the maximum pressure is reached.

      As for the bladder in the pressure tank it shouldn’t need to have air added to it but if the pump is short cycling and by that I mean the pump turns on even with the slightest amount of water usage then I suggest you read:
      How To Check The Bladder In Your Well Pressure Tank

      I hope this helps,

  3. Denis says: sewer pipe runs under my attached garage floor and down under my driveway. i live in southern wisconsin so when that frost line starts getting down by mid january the pipe freezes up always in about the same spot about middle of drivway.i do have a drain in the garage thats how i know when it freezes cause it will back up there. some years it doesnt freeze but usaully will at least once. i use a power washer with a self propelled tip. it takes about 1 1/2 hours to break open, plus having to pump out the water until it opens up. i have a concrete driveway. what can i do to prevent or correct so i don’t have this problem anymore? also approx. price range to correct this? thank you Denis

    • Redwood says:

      Hi Denis,
      A drain line should never freeze even when it is above the frost line. The drain lines don’t freeze because they are pitched to drain dry when they are not in use and when in use the water should be in sufficient volume that it does not cool off enough to freeze while in the pipe. There are two situations when a drain line can freeze. The first is when there is a slow leak such as dripping faucet or, leaking flapper on a toilet where the volume is insufficient and ice starts to form in the pipe with the ice plug eventually completely blocking the pipe one drip at a time. The second situation where a drain can freeze is if there is a belly (or, sag) in the pipe where water always remains without draining dry, if the belly reaches freezing temperatures it will freeze and block the pipe.

      I suspect that your sewer line freezing is caused by a belly in the pipe where the water that remains in the pipe finally is reached by the frost line and freezes. There is no method to repair a belly in a sewer line other than digging the line up and replacing at least the bellied portion of the line. Usually the replaced section will extend for some distance past the belly in order to get the pitch required on the pipe. Usually bellies are caused by an improper installation where the pipe was not bedded properly on compacted soil and the soil settling created the belly. There are other causes such as leaking joints, and frost heaves, but usually compaction and bedding is the issue.

      As for cost of the repair one of the things that will need to be done is a camera inspection of the line. You can read more about camera inspections at “Sewer Line Requires Repair or, Replacement?” which will allow you to see inside the pipe to see the exact extent of the bellied section as well as anything else wrong along the length of line, which will determine if additional repairs are needed anywhere else. The camera has a locating transmitter or, sonde built into it which will allow the location and depth of the belly to be determined which will allow a fairly accurate estimate of how much of the line has to be dug up to get the required pitch. This information will be needed to get an accurate quote for the repair job as the cost is determined by the depth and length of the excavation. Get several bids on the job and go with the one that you feel most comfortable with, that is all I can say about the pricing as prices vary widely across the country in different market areas.

      Good luck with getting the repair accomplished and I hope this information is helpful to you,

  4. Alexandria says:


    I seem to have frozen water pipes. I heat with oil, and have forced hot air. Nobody is living there at this time, but I need to correct the problem ASAP. I was told to open the faucets, shut off the main valve of water, and open the cabinets to let the heat get directly to the pipes under the sinks (which I did). My big concern is that does it put my hot water heaters in jeopardy? They are downstairs and little heat gets there. I have conflicting reports. Someone told me as long as the water main is off, it will be ok. Other people say that unless it’s drained, it could freeze the water in the water tanks. Who is correct and how do I fix this problem? I am on a fixed budget, and really don’t want to pay a plumber if it can possibly be helped. Please help!!! 🙂 Thank you

    • Redwood says:

      Hi Alexandria,

      Is this a situation where the heat has been turned off?
      Were the water heaters turned off?

      In your situation turning off the main valve the cranking up the heat is probably the best start.
      Then cracking the main valve slightly open to check for leaks and additional freezing.
      Given the time the pipes were frozen without anyone being there it is almost certain you will have some burst pipes and need the services of a plumber.

      Thanks for commenting,

  5. gil j says:

    I too have frozen pipes. I do however believe it is froze somewhere in the supply line coming in. We are in a mobile home and on a well. Under home is well insulated and heat tape is working. Is my pump in danger of burning out while waiting for the ground to thaw? If so what precautions should I take? Also how might I tell if my well pump is working? Thanks Gil..

    • Redwood says:

      Hi Gil,
      It sounds like you may be frozen up. To figure where your line is frozen depends largely on how it is configured and available points to open sillcocks and drain valves to see where water is available and not available. In some cases a connection may have to be broken to check for water flow then put back together again. Once you narrow down where the water flow from the well stops you are close to finding where the line needs to be thawed.

      If your freeze up is in a place where the pressure switch is calling on the pump to run but the water cannot reach the pressure switch and storage tank then the pump is dead-heading and in danger of being damaged if it hasn’t been damaged already. Are you able to tell if the pump is running or, not? Can you tell if water is available at the pressure switch and pressure tank? If you have a submersible pump do you have the electrical skills and test equipment to take measurements and determine if the pump is running and running properly? If not I would consider calling in a pro as soon as possible.

  6. Anji says:

    We live in NW Arkansas & our copper pipes beneath our old house have frozen. There are several crawlspace openings beneath our house that are not sealed off. The copper pipes are not insulated and our home is heated by gas floor heat all. There is a wall gas heater in the bathroom that has been on high for about 24hours now, and the bathroom is steaming hot and there is condensation on the bathtub faucet and it appears as if there has been some water coming out from somewhere. I have all the faucets open so water that might thaw can exit the pipes. Can i put a space heater under such a large open space & expect the pipes to thaw? How can i real off the crawl Space openings to keep the heat under there? Would plasTic bags over the openings work or do i need to get styrofoam? My husband is @ drill this weekend & by the time he will get home it will be very late. It is only 25degrees now and it hasN’t been above freezing for over a week now. It will get down to 5 degRees tonight & this is going on 2 days without water or working toilet. We need 2 do this ourselves to avoid high costs we can’t afford. FlooR heaters will not heat pipes because the house already has poor insulation problems that i was planning on fixing before this. Plz help

    • Redwood says:

      Hi Anji,
      I would recommend placing Styrofoam in the vent openings and getting some heater(s) going under there to warm up the crawlspace.
      I fear though that the condensation in the bathroom may be coming from a burst pipe which is probably leaking water down into the crawl space. You probably do need a plumber if that is the case.

      With copper pipes a plumber could use an electric pipe thawing machine and rapidly thaw everything and in addition could fix any leaks.

  7. Mike says:

    I left my garage door open for a while as I was snowblowing (bout an hour, wife out of town, keeping an eye on the kids playing in the garage of all things). Couple hours later I go to my daughters bathroom directly above the garage and I attempted to turn on the water to the sink, toilet and tub there without success. I put the space heater on under the sink and next to the tub/toilet with a little success. Put the space heater on in the garage where I think the pipes are and now the sink is working fine although hot water only. The toilet and tub will work only when the sink is running, and with only hot water also. The toilet refiller is weak, and the tub will instantly lose all water pressure when I flush the toilet or the sink faucet off. Right now I am continuing to run the space heater in the garage and have the sink/tub set to give out trickling water. I have no idea if the cold water pipe burst, although I have found no signs of a leak after inspecting the bathroom/garage drywall or looking in the basement anywhere although the garage is on the concrete foundation and not over the basement living quarters. Any other advice, tips, etc would be greatly greatly appreciated!!!!

    I think I alluded to this but the pipes are not exposed/visible to the naked eye and are concealed by drywall.

    Thanks in advance!

    • Redwood says:

      Hi Mike,

      It sounds like a classic case of the cold supply freezing up.
      The only water you have now is the hot which when you run the faucet back feeds to the toilet and tub.
      You want to be very careful and not allow that to happen as the hot water running into a cold toilet can cause it to crack.
      This is a problem that many people have with a bathroom over an unheated garage. Its just a bad design!

      Get as much heat as possible going into the garage. Space heaters, open doors to the house with fans, whatever it takes to warm that garage up. You may also find where the pipes leave the basement to run up the garage wall to the ceiling and direct the hot air from a hair dryer up that wall if you can. The faster you get this thawed or, prevent more freezing the less likely pipes are to burst.

      If you have metal pipes you may want to consider calling a plumber with an electric pipe thawing machine to get the pipes thawed quicker. After the pipes thaw is when you may find the burst pipes, right now the ice isn’t running out of the hole.

      In the future you might want to make sure the garage door only opens long enough to get in and out, and you may want to consider putting some form of heat in the garage to run on the coldest days when freezing may occur.

      I hope this helps,

  8. Dean W. says:

    I think out pipes froze last night, when i flush the toilets or try to run water nothing is happening. I have no ideal where it would be froze if they are, we just bought this house last week and i am not familiar with the layout. How would I go about thawning the pipes if they are indeed frozen?

    • Redwood says:

      Hi Dean,
      It does indeed sound like you may have frozen pipes or a water supply related problem.
      I have no idea of the construction of your home or its systems.

      If you are on a well system the there may be a problem with the well pump check to make sure the pump is on and the circuit breaker has not tripped and pressure is indicated on the gauge. Tap the gauge lightly to make sure it is indicating correctly.

      As far as frozen pipes with the arrival of the frozen weather it is certainly possible. I don’t know if you have a basement, crawl space, or a slab foundation but wherever you can get access in a basement or slab pipes could be found for tracing and finding a cold spot where they may be exposed to a draft causing freezing. Try a hair dryer to warm the frozen area or directing a heater into the crawl space. Seeing as everything is off I would advise looking at main water supply lines.

      In the event of a slab foundation look for possible freeze areas in the meter box if installed out side, or where the main water supply comes up into a wall of the home. This could be a lot tougher to figure out and you may want a plumber with a electric pipe thawing machine if you have metal pipes.

      You may want the plumber with the pipe thawing machine in either case if you have metal pipes and ask him for advice on insulation or possible use of heat tape.

      If your pipes are plastic the only thing you can do is warm the area where the pipes are frozen.

      Thanks for posting,
      I hope this works out for you without any burst pipes,

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