Conducted water pressure gauge test to verify if there's a leak, and confused by the results

Context: 3 storey house, ground and middle floor have a gate valve shutoff (the round turny-handle one, not the lever one). Top floor has no shutoff valve suspected leak is an in-slab section of pipe, and the concrete ceiling below shows signs of higher moisture. Enough to damage skim coat and paint in the bedroom below but not enough to drip, so suspected leak must be smaaalll mains water pipe and internal pipe are all copper pipes, no plastic/HDPE/whatever they're called test conducted in the middle of the day, about 29C/85F My test procedure was install pressure gauge in the garden, near the mains water shutoff valve turn off ground and middle floor water supply turn off mains water, measure pressure (95 psi = 6.55 bar) wait 45min, dropped to 91 psi (=6.27 bar) wait a further 15min, appears to have gone back up to 95 psi or so I'm confused by a few things why would pressure go up again? (besides the possibility of a faulty gauge, which is brand new) the suspected leak is on the top floor. Should I find an outlet on the far side of the suspected leak to pressure test? (so the suspected leak location is in between the mains water valve and the pressure gauge). I thought in theory it's all a closed loop system when mains is turned off so the pressure gauge location wouldn't matter, but wanted to ask this anyway because I suspect a small leak, should I leave the test going overnight? Originally I wasn't paying much attention to the numbers themselves, only wanted to see a drop in pressure to validate a leak, but if my gauge is correct, 95psi seems really high. Far higher than the measurements from youtube videos I was learning this procedure from. I will go compare this with my water supplier (I'm in Asia, this may take a while lol). I wonder if it's too high for old pipes and/or typical installation methods + wear/tear over time (building is almost 40 but most pipes are probably 15yo, when I think it was last renovated)? Thoughts on this point are also appreciated. As you can see, I like bullet points, hah. Thanks in advance for any help! submitted by /u/Advanced-Button [link] [comments]

Context:

  • 3 storey house, ground and middle floor have a gate valve shutoff (the round turny-handle one, not the lever one). Top floor has no shutoff valve
  • suspected leak is an in-slab section of pipe, and the concrete ceiling below shows signs of higher moisture. Enough to damage skim coat and paint in the bedroom below but not enough to drip, so suspected leak must be smaaalll
  • mains water pipe and internal pipe are all copper pipes, no plastic/HDPE/whatever they're called
  • test conducted in the middle of the day, about 29C/85F

My test procedure was

  • install pressure gauge in the garden, near the mains water shutoff valve
  • turn off ground and middle floor water supply
  • turn off mains water, measure pressure (95 psi = 6.55 bar)
  • wait 45min, dropped to 91 psi (=6.27 bar)
  • wait a further 15min, appears to have gone back up to 95 psi or so

I'm confused by a few things

  • why would pressure go up again? (besides the possibility of a faulty gauge, which is brand new)
  • the suspected leak is on the top floor. Should I find an outlet on the far side of the suspected leak to pressure test? (so the suspected leak location is in between the mains water valve and the pressure gauge). I thought in theory it's all a closed loop system when mains is turned off so the pressure gauge location wouldn't matter, but wanted to ask this anyway
  • because I suspect a small leak, should I leave the test going overnight?

Originally I wasn't paying much attention to the numbers themselves, only wanted to see a drop in pressure to validate a leak, but if my gauge is correct, 95psi seems really high. Far higher than the measurements from youtube videos I was learning this procedure from. I will go compare this with my water supplier (I'm in Asia, this may take a while lol). I wonder if it's too high for old pipes and/or typical installation methods + wear/tear over time (building is almost 40 but most pipes are probably 15yo, when I think it was last renovated)? Thoughts on this point are also appreciated.

As you can see, I like bullet points, hah. Thanks in advance for any help!

submitted by /u/Advanced-Button
[link] [comments]