Cost to find a leak in new PVC plumbing

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by nelsonba, Aug 10, 2006.

  1. nelsonba

    nelsonba New Member

    Messages:
    116
    Location:
    Minnesota
    I've got a finished bathroom that failed an air test. I need to find the leak(s) and repair it(them). I understand that this will involve cutting into some walls/ceilings. I had a plumber come out to give me a quote. He said they would have to re-plumb the entire drain and vent system. I'm not sure if everything is up to code since I had a friend who used to be a plumber (and is not licensed) do the plumbing. Is it really necessary to redo the entire system? If so, what's a fair price range? I realize no-one can give an accurate price without seeing it, but how about a range? The quote I got was $8,000. When I originally started the bathroom I got a quote of $4,500 to rough-in the entire system, including water supply lines. That's looking pretty good right now. Lesson learned.
  2. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    Is it a slow or fast leak?
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,812
    Location:
    Cave Creek, Arizona
    leak

    Seal it up and do a water test to find the leak. An air leak would be almost impossible to find at this stage of the game. You would probably have to expose the entire system to find an air leak.
  4. nelsonba

    nelsonba New Member

    Messages:
    116
    Location:
    Minnesota
    It went from 5 lbs to 4.5 lbs in two minutes according to the plumber. Not sure if that would be considered fast or slow. If I did a water test, wouldn't I have to open everything up anyway to see where it was leaking?
  5. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The leak could have been at a temporary seal. Or it could be a drip somewhere. Dripping water will reveal the source of the leak. Fixing that will be a lot less than $8000.
  6. prashster

    prashster New Member

    Messages:
    941
    Is the leak in the drain or the water supply?

    If in the drain, and leak is under a slab, then I'm not sure a water test will reveal the location. The only recourse then would be to bust up the concrete and find the leak; basically re-rough in the drain. That might be why the est is so high.

    If the leak is in the water supply, then I can't imagine it should be so much. You can try to id the spot yrself with a water test. But in the worst case, even if you had open all the walls and ceiling and redo the water lines, it shouldn't be an $8000 job.


    As another point of ref: I was quoted $6500 for a complete bathroom rough in. Ended up doing it myself. 90% of the effort is in the drain.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,812
    Location:
    Cave Creek, Arizona
    leak

    With a water test you would have to open the wall where the water appeared on the floor. I cannot imagine a leak under the floor, unless it was not tested prior to concrete placement or the concrete crew putting a stake through it. But even then, most inspectors require a second test after the upper plumbing is installed, but before the sheetrock is installed. If no leak was shown then, the most likely cause of the leak is a drywall nail, or similar, through the pipe above the floor. If those prior tests were not made, then your leak could be anywhere, and if it is under the floor you may never find it.
  8. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,715
    Location:
    Central Florida
    I assume from the low pressure used this is in the DWV system.

    If all the plumbing is exposable, then I'd get a bottle of soap-bubble solution and start spraying joints, looking for an air leak. Do the exposed pipes first, and pray the leak is there. If it isn't, you can start chopping up walls, etc. If you can isolate and individually test sections of it all, you might be able to narrow the area where you have to chop up walls. One long-shot: call a leak detection outfit and ask them if they can help. You might be able to pump up the system to where a leak could be detected by their super-sensitive acoustic equipment. (Sch 40 is good for what? 160 psi?) I used an outfit called Sleuth in Tampa, but I'm sure there are lots of them all over.

    The stupid question: why did you wait to do the test until after everything was closed up?

    Full disclosure: When I did my leak test on the supply side, it held fine at 40psi, failed at 60 psi because I had neglected to cement one CPVC joint. Primer alone was doing the job at 40 psi.
    Last edited: Aug 11, 2006
  9. coach606

    coach606 New Member

    Messages:
    144
    Location:
    Illinois
    Another view...

    I feel for you, man. There is nothing worse than dealing with a leak after finally closing up your bathroom. It seems worth testing it for the leak before you give in and have to rip everything up. If you find the leak and fix it, all you have is to redo the wall. Is everything tiled? Is there access on the other side of the wall? How about from below?

    My upstairs bath has a closet right behind the mehchanicals wall. I have huge access panels back there. If you have a closet behind the wall you probably access it from that side without having to worry about chopping up the drywall or tiling. I just cut a big piece of drywall out and screw it back in when I need to. No one sees it because it's in the closet.

    I guess I'd try a water test. I believe you could even put a few drops of food coloring in there to help make a leak more obvious. If you can find the leak it's pretty easy to fix with pvc. Just saw out the leaky fitting and redo.

    As a homeowner and a DIY'er, my advice is to try to gain access to the area by cutting drywall or making an access panel in a closet. Buy a test balloon and fill your system for a water test. Check for leaks, baby! You can probably accomplish the repairs yourself, too, or hire a pro, but fixing one leaky pvc joint (or even a few) with the pipes already exposed shouldn't be too expensive. Had a guy cut out an 80 year old tub drain and replace a whole linkage of cast iron pipe as well as install a new tub drain and overflow for under $500. He did a great job, too and it squirting in his eye while he sawed and everything.

    Find the leaky joint. Odds are it's just one or two places. Installing pvc is pretty simple. Assuming he used proper primer and cement, it's likely most of it is okay.

    Good luck.
  10. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    If the work was the bathroom, then that is what should be inspected. You would need to find a way to isolate the bathroom to test it.

    Before you start tearing everything out, figure out how to divide the system into pieces and test each piece until you find the leak.

    You should figure out how to do that test yourself. You should KNOW it is going to pass the test before the inspector comes.

    Don't try testing a DWV system at high pressure unless you are prepared for a spectacular failure. And if you do a high pressure test, DO NOT USE AIR! Schedule 40 PVC pipe will take any pressure you might apply, but DWV joints will not. DWV sockets are shallow and looose fitting, and many DWV joints are made in difficult situations where the process of "primer and cement on both surfaces and 1/4 turn at assembly" is not applied.

    I saw a plumber (at least that's what it said on his truck) try to put a pressure system together with DWV fittings because his local supplier didn't have 1 1/2" Schedule 40 fittings. After blowing out elbows and tees three times, he got the right fittings.
    Last edited: Aug 11, 2006
  11. Rope Tow

    Rope Tow New Member

    Messages:
    5
    Slow Leak

    .5 lbs in two minutes is pretty slow. You might not be able to hear or feel it. I've just finished testing my PVC. Make sure the air pressure and temperature stabilizes before starting your test. Hot air from the air compressor is not uncommon, and will shrink of course when it gets into the 72+/- house. What happens after two minutes?

    If it continues to loose pressure, my 2 cents is to spray all the exposed area and definitely the test caps that you can with soapy water and hope you see bubbles. If not, I would fill it with water and wait around with a bucket!

    I had a slow leak in my system - had forgot to glue one vent 90 in the attic. Finally, at about 6 lbs, it popped off (bang!) and I glued it and I'm all set.
  12. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,358
    Location:
    Yakima WA
    Since liquid leaking is easier to see than air, here's what I consider. Fill the pipes with water, the colored water might be a good idea, and then apply pressure. Check all the visible joints first, but if nothing appears, then start cutting drywall. If you are any kind of DIYer, you can repair drywall for lots less the $8K! You made no mention of any part of the drain being in a slab, but if it is, then cutting the slab portion out would be the last step. Redoing the entire drain system seems pointless since to do so you would have to exposed everything anyway. Also seems to me that your friend used his past experiance to persuade you do let him do a cut-rate job, he should stand the expense of the repairs. At least come in and help you find the problem. I would also be my opinion that you should have a licensed plumber at least inspect the job and make sure the venting, fittings, slope, pipe sizing, etc. are up to code.
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