How do you thaw out pvc drain pipe in driveway that has frozen?

Beagle Mom
by Beagle Mom

I have a drain in my driveway that is approximately 50 feet of 4" pvc pipe. Due to this freeze/thaw cycle this winter, it has frozen up on me three times this year. I was told to put rock salt down the drain, which I have used about 500 pounds of rock salt so far this winter and it still freezes on me. I have had to call a plumber to jet the line, which costs me $400. I was wondering if there was a way to thaw out the ice from the pipe so I don't have to shell out $400 to have it professionally done.

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  5 answers
  • GrandmasHouseDIY GrandmasHouseDIY on Feb 12, 2019

    Hi Candi, the first thought that came to my mind was a hose attached to one of your faucets in the house. Turn the water on warm and just let it go down your drain.

  • Dwp7470b Dwp7470b on Feb 12, 2019

    Rock salt is the worst advice. You can damage it or the salt itself can accumulate and cause a Clog just like Blocked arteries.

    This, even as Hot Tea and Hot Coffee assist removing plaque from your arteries your resolve here is similar:

    You thus need to Boil Water and Pour it down the Drain regularly.

    That will melt any freeze-up. 1 gallon an hour for 6 hours.

    If it is still blocked after 6 gallons, then you add refined table salt to your boiling water. About 3 teaspoons a gallon.

    If that doesn't work, it is not ice but instead leaves, dirt or moltings from rats or possibly a dead mouse. For that you will need a Drano Like Acid to clear up the clog and you need to read the bottle before you buy it to make sure it says: PVC SAFE.

    Do not ever use anything that is not Specifically Marked as: PVC SAFE.

    A list of items that are not safe for PVC is available online, just search for:

    What cleansers are not PVC Safe?

    On Google.

    That list includes unfortunately: Rock Salt.

    • See 3 previous
    • William William on Feb 12, 2019

      I said heat cable not heat tape. Heat tape is for wrapping around pipes for indoor use. Heat cable, as I advise, is for outdoor use. Just like for roof, gutters, and downspouts. AND it is safe for PVC pipe. Google it.

      Hot water would cool enough in a 50' run that it would be ineffective and freeze anyway.

  • William William on Feb 12, 2019

    Some kind of heat cable on the discharge line. You would only do this if your discharge line is hard piped with PVC. This is not something we recommend if you are using the thin flexible discharge line. You could use a roof and gutter de-icing cable and run it through the discharge line and plug it in as needed. DO NOT use pipe heat tape. Pipe heat tape is meant to be used on the outside of the pipe in indoor applications only and is not to be exposed to the elements.

    • Dwp7470b Dwp7470b on Feb 12, 2019

      Exactly why I said Hot Water William. Heat tape is definitely out. As is any chemical not PVC Safe.

  • Russbow Russbow on Feb 12, 2019

    William, above is right on. IF you can get the tape, inside the pipe, Not knowing how and what water you are putting IN< and where it comes OUT, might change the advice, but the heat cable is not stiff, so getting it all the way through might be difficult. You could try adding a large floating object and then flushing water through to do it, or any idea to get it all the way through.

  • Lynn Sorrell Lynn Sorrell on Feb 12, 2019

    Easy install internal pipe heater to get it thawed first boiling water w/ loads of salt in it. run hose to kitchen/utility sink then run hot water into drain pipe let it flow steadily slowly to slowly melt ice, adding salt . After it's thawed out install the internal pipe heater. What is the pipe draining? Is it from house/gutter? This weather will not last & this degree of cold(not sure where you live) only comes every 10yrs or so maybe you can just wait it out then install the pipe heater.