Will White PVC pipe crack if water freezes inside it?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by nestork, Oct 14, 2012.

  1. nestork

    nestork Janitorial Technician

    Messages:
    98
    Location:
    Winnipeg
    My nephew just puchased a house that's about 9 years old. He has a metal water hydrant on the back of his house, but the handle to turn it on is at an angle to the exterior wall of the house, and this makes me think it's NOT a frost free hydrant.

    He removed the tiles in the suspended ceiling in the basement and could only see white plastic tubing with no shut off valves in sight.

    The woman who owned the house before him says she doesn't know anything about it.

    I have no experience with PVC water supply tubing, and I'm wondering if an indoor shut off valve isn't necessary with PVC water supply piping because there's enough elasticity in the plastic to stretch and shrink as the water freezes(?)

    Any advice on what to do in this situation would be very much appreciated.
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    It will freeze and crack for sure.
  3. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,396
    Location:
    Yakima WA
    Any pipe will break from frozen water. Side note: PVC is not supposed to be used for water inside a home. The PVC should be replaced and a frost free hose bib installed. A shutoff valve inside would help, but the pipe after the valve would have to be sloped so it would drain when the valve was closed. Hoses must be removed from frost free bibs or the bib will freeze and break.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    It might be CPVC, and if so, is approved for interior supply lines. You either need an interior shutoff and to remove the hose from the thing when there's a chance for freezing, or to replace it with a frostfree hose bib. SOME, by no means all, frost free hose bibs drain whether there is a hose attached or not, and if the people are forgetful, that is something to search out (Woodford makes some and probably others). A nice upgrade is to get one of the hot/cold frostfree hose bibs. Good for washing the dog (or you!) and maybe the car. Obviously, it would require running hot there as well as the existing cold. I know both Moen and Woodford both make them, and probably others.

    Pex itself may not split, but the fittings wouldn't be so lucky if they froze.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,258
    Location:
    Cave Creek, Arizona
    PVC will only "stretch" if you have hot water in it, otherwise it will break 'somewhere".
  6. nestork

    nestork Janitorial Technician

    Messages:
    98
    Location:
    Winnipeg
    OK, according to the long range weather forcast, it's not going to go below freezing at night for a week to 10 days yet, so we have some time.

    The ceiling is finished in his basement, and I'm concerned that valve has been drywalled over. I intend to cut through the ceiling under where the hydrants are on the outside to see if there's a valve to be found.

    If that fails, I'm thinking the best bet would be to attach a short piece of rubber hose to each outdoor hydrant, insulate the outdoor hydrants as well as we can and open each valve a bit to allow cold water to trickle out at night, thereby keeping the valve and piping above freezing.

    Is there any better option anyone can think off?

    I''
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    Heat tape, but this assumes there's somewhere to plug it in. Or, cut the pipe and install an inline interior shutoff. Since you already have a hole there, go buy a pop out inspection panel to cover it back up. You may need to trim the hole so one of the pre-fab panels will fit.
  8. nestork

    nestork Janitorial Technician

    Messages:
    98
    Location:
    Winnipeg
    Yeah, as soon as I hit the "submit reply" button on that last post, it occured to me: Why not just cement a new valve in. That way it doesn't matter if we can't find the original shut off.

    I've never worked wth PVC tubing before. Is it like ABS where you have to apply the cement to both the pipe end and the socket (I expect so). Also, if there's water leaking from the pipe, would that affect the installation of the valve like it would if I was working with copper piping?

    I don't know if the pipe will move (to spread apart) if I cut it to glue in a valve. I know there's no such thing as a slip coupling for plastic pipe. In that case, what can I do? Use a PVC union?
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
  10. kreemoweet

    kreemoweet Member

    Messages:
    377
    Location:
    Seattle. WA
    So you're saying the drywall was just recently installed? Since this outdoor spigot has apparently been in place for many years, it is surely OK, except
    if the indoor shutoff valve has recently been covered over, you have a problem. There is no reason to suppose the shutoff valve is anywhere near the
    outdoor valve. You should backcharge the nitwits who covered up the shutoff.

    Insulation on the exterior valve is useless, and in your climate, leaving it to dribble is probably useless also.
    Last edited: Oct 14, 2012
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