Losing water pressure = leak?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by jptemp, Jan 9, 2013.

  1. jptemp

    jptemp New Member

    Messages:
    4
    Location:
    CT
    I am stumped. I have an apartment where the bath and kitchen fixture and water heater are all fed by one 1/2" line with a ball valve. Shut off the ball valve and no water goes to any fixture.

    I shut the valve off, and the next day I turn on a faucet and there is almost no pressure. Shouldn't the lines stay pressurized over night? There are no water leaks that I can see. None of the fixtures drip. the pressure relief valve on the water heater does not drip.

    It seems impossible.
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    I would not expect to find much in the way of residual pressure. A few drips in the toilet tank and you would never notice. If you want to get serious about your "testing" you could put a pressure gauge in the line and see what happens.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,009
    Location:
    New England
    Anyone flush the toilet? Since the pipes don't really stretch at the pressures in a normal home, that leaves maybe the rubber/plastic hoses to the faucets that can act like a bladder to help hold the pressure. All it takes is a VERY small amount of water coming out somewhere to relieve the pressure. That could happen just by the water cooling off, especially if you turned the WH off, since the cooler water is more dense (i.e., takes up less space). Do you have an ice maker on the frig?
  4. jptemp

    jptemp New Member

    Messages:
    4
    Location:
    CT
    No, the toilet was out do redo the floor.

    About half of it is type A pex and half copper. Would that do it?

    Water heater was on and no ice maker.
  5. jptemp

    jptemp New Member

    Messages:
    4
    Location:
    CT
    The toilet was out at the time. I could put a pressure gauge on the kitchen sink, all I would need is an adapter to a male garden hose thread. I suspect the pressure will drop from 50 to around 10.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,636
    Location:
    Cave Creek, Arizona
    Why are you worried about it? Unless the pipes are not all visible, you obviously do not have a leak. The pressure could drop for any number of reasons, but unless it were ZERO, a leak could not be one of them.
  7. jptemp

    jptemp New Member

    Messages:
    4
    Location:
    CT
    I'm worried about it because the pipes are not all visible and it might be leaking somewhere inside the walls, creating mold, wood rot, etc.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,009
    Location:
    New England
    Just the simple act of the house dropping in temp might would make the pressure change. Colder water shrinks until it gets to about 34-degrees, then starts to expand again (the reason ice floats).
Similar Threads: Losing water
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Losing Water Surface Feb 9, 2013
Plumbing Forum, Professional & DIY Advice, Tips & Drain Noise/Toilet Losing Bowl Water Dec 23, 2011
Plumbing Forum, Professional & DIY Advice, Tips & Losing Hot Water Pressure (only) May 23, 2008
Plumbing Forum, Professional & DIY Advice, Tips & shower pan losing water, but not leaking... Apr 10, 2006
Plumbing Forum, Professional & DIY Advice, Tips & new sand point system losing pressure Feb 2, 2012

Share This Page