Mysterious Water/Pipe noise at midnights

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Jessicayiyi, Oct 30, 2013.

  1. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    This is a very complicated issue that has been going on since late Sep 2013. I will try to start from something simple and get into something more complicated.

    Something Simple:
    - We live in a town home, no one above us. There is an attic with some pipes, etc.. We have been living here since Feb 2013.
    - We hear water/pipe noise from our ceiling of bedroom at midnights.
    - The time is kind of random: 1am, 3am, 4am.
    - The noise usually lasts for 1 hour. On a couple of days, it lasted for 3-4 hours.
    - The noise sounds like pouring water into an empty container, consistent “pouring” for 5 seconds every 15-18 seconds. There is also sound of water dripping which resonates in the entire attic (usually this is the sound that wakes us up). Also sound of water bubbling once in a while after the “pouring”.
    - Here is a dropbox link for downloading a recording of the noise. https://www.dropbox.com/s/zrsj86fyfzfekd0/Memo.m4a. Toilet flushed at 4:20.


    To make things more complicated:
    - On the 2nd or the 3rd midnight we heard the noise, we got up and went to check on what was going on.
    - We flushed the toilet and immediately we heard a very loud hammering noise that repeated for a couple of times. We tried flushing another 2 toilets and same hammering sound took place. We were certain that this does not happen during day time.
    - We called in a plumber the next day and described everything to him (because we cannot reproduce the noise), he looked into the toilets and said the parts are old so there could be leaking. We had him replace everything in all the toilets. It did not help.
    - On another midnight soon after, at 1am, when the same water/pipe noise came up and the same hammering sound came on after flush, we called in another plumber at 2am. He tested the pressure regulator and said the pressure dropped when the hammering sound came on so he installed a new regulator.
    - Immediately after the regulator is replaced, the hammering sound went away no matter how much we flush the toilets.
    - We were very happy and slept well for a week or so, but the water/pipe noise came back one morning at 4am. Tried flushing the toilets, no hammering sound and no change in the pattern of the water/pipe noise.


    To make things even more complicated:
    - Before all the noise (water/pipe, hammering) appeared, we had a leakage from the fire sprinkler pipe in the ceiling/attic that created some mass upstairs. Fortunately, everything is covered by HOA.
    - A fire safety company came more than a week later and repaired the leaking pipe. It took quite some time before they came to repair, because --- according to HOA --- not many companies are familiar with our community and they do not know where the valves are.
    - The first midnight after the repair, we started to get the water/pipe noise.
    - The plumber checked the attic (as we believe the noise was coming from there), and told us that there is no plumbing but only fire sprinkler pipes. Highest level of plumbing is shower which is ~2.5 feet below the attic.
    - We did one experiments one midnight when the noise came on:
    1. We turned off the main valve to the entire house.
    2. We drained all the water in the house (no water is coming out from the lowest faucet)
    3. The water/pipe noise kept going for another 1-2 hours until dawn.


    Current situation:
    - We sent the recording of the noise to the fire safety company. They listened to it and insisted that the noise is not coming from the fire sprinkler pipe according to their many years of experience and refused to come out and do anything.
    - We sent the recording of the noise to the plumbers who did all the toilet, regulator work (we paid them). They listened to it but they could not figure out what might cause the noise, and cannot do anything if we are not able to reproduce the sound during day time.
    - We sent the recording of the noise to the HOA. They said they could hardly hear anything in the recording and suggested us to 1) go ask our neighbors whether they are hearing the same thing, and whether they take shower or do laundry at night? 2) Check if there are rodents in the attic.

    We are feeling very exhausted & frustrated at this moment from what have happened and from sleep deprivation. Any suggestion, comments or help would be very much appreciated.

    Many thanks in advance!

    Jessie
    jiayingfeng(at)outlook.com
    Last edited: Oct 30, 2013
  2. Caduceus

    Caduceus Master Plumber

    Messages:
    99
    Location:
    Pittsburgh, PA
    Are you aware of any sump pumps in your home or in the neighbor's home? If a sump was connected to the drainage plumbing and you shared any pipes with a neighbor, the sound may be heard throughout the plumbing system even with your water turned off. Though it still doesn't answer why this started after the fire system pipe repair unless a drain valve on the fire system is leaking or was left open.
    Another question. Is your fire system connected to a water supply for your town home only or is there a main shut of for all units in a mechanical room and they share the same system? I have to wonder if there is a RPZ backflow device that has had issues from the time of the repair on the fire system and may be discharging.
    If this only happens in night time hours, those are the prime times for thermal expansion. The fire system company may have altered something in the piping. Without a thorough examination of the whole system (water and fire) it's going to be tough. These may be good questions for the plumber/fire system company, also.`
    Last edited: Oct 30, 2013
  3. Reach4

    Reach4 Active Member

    Messages:
    1,917
    Location:
    IL
    Interesting. Until I saw the times were random, I was wondering if it was a water softener or filter regenerating.

    Your turning off the water and draining the pipes would seem to eliminate a lot.

    What kind of heating do you have? Hot water?

    Neighbors... up to something? Brewing moonshine in the attic? If you put your ear to the shared attic wall, is the sound louder? Can you put your ear to the fire sprinkler pipes during the noise-- or at least feel the pipes for vibration?

    Have you had much rain?

    I suggest uploading your sound recording on a public site. Maybe search for post file public

    I think your fire sprinkler pipes are the prime suspect here, but then why would the neighbors not hear?
  4. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Dear Reach4,

    Thank you very much for the suggestions. Here is a dropbox link for downloading the audio. https://www.dropbox.com/s/zrsj86fyfzfekd0/Memo.m4a. Hopefully you can hear something... It can be tricky.

    I will try to answer some of your questions.

    - It would be difficult for me to put my ear to the pipes because it is located in the attic and there is only a small opening and the ceiling is not strong enough to support a person's weight. So since it is not a real attic that we can use, we don't have the wall to listen to either. Will try to feel the vibration though.
    - We live in Southern California. It hardly rains.
    - For heating, you mean the heat for water or for the entire house? We have never used the heat in the house because it does not get too cold here. For water, there is a water heater.

    Thx again!

  5. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Dear Caduceus,

    Thanks for the reply. To be honest, I do not know how to answer your questions because I do not know sump pump, RPZ backflow device. I will forward these questions to plumber/fire system companies.

    But I believe the fire system for all the units share the same system because it is covered by HOA.

    Thx!

  6. Reach4

    Reach4 Active Member

    Messages:
    1,917
    Location:
    IL
    That is a really good sound recording. Are you sure you are not funning us? That recording is way too good. You sound too sincere for this to be a hoax.

    Here is my guess: somehow the sound from your neighbor's bathroom transfers to your bedroom. Shared cold air return, or what? Play a radio in your bedroom, and listen from the neighbor's bathroom.

    Anyway, the sounds are from a toilet. The toilet self-flushes or is self-refilling. At least one of those is from the neighbor actually going in and operating the toilet flush, possibly in response to trying to cure the problem. http://www.youtube.com/watch?v=0c2GhDZDtyM http://www.fluidmaster.com/toilet-runs-on-its-own-ghost-flushing.html

    The cure of the continual toilet should be simple. The privacy problem requires major construction IMHO.

    Until this is cured, be careful what you say in the bedroom. Run a big box fan to mask the noise while you try to sleep. Make private sounds elsewhere.
    Last edited: Oct 30, 2013
  7. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Hi Reach4,

    Thank you for the reply. Because our HOA said that they cannot hear anything so we are worried that it may not work for everyone.

    We will definitely talk to our neighbors. But one thing confuses me is that we never heard anything before sleep or other time during the day when the room is also quite. The noise only comes out during midnight 1-5am.

    And thanks for reminding us about the privacy issue. We appreciate your help very much!
  8. Reach4

    Reach4 Active Member

    Messages:
    1,917
    Location:
    IL
    OK... I am not a pro, but I like a good mystery. Here is my try at an alternate explanation leading to a solution.

    You have a pressure regulator on your incoming water. So does your neighbor maybe.

    1. Suppose that neighbor's regulator is bad or missing.
    2. Further suppose that water pressure in the city water is higher in the middle of the night.
    3. Suppose there is something about their toilet valve which makes it leak in the face of excessive pressure.

    What do you do? Is there was a way to fit a gauge before your water pressure regulator? Maybe that reading would correlate to when you hear the sounds. It would be too much to hope that they provided a pre-regulator tap. :)

    OK... here is one that could work. Put a pressure gauge on the neighbor's outside faucet, with their permission. Go outside to take your readings. http://www.homedepot.com/p/Watts-3-4-in-Plastic-Water-Pressure-Test-Gauge-DP-IWTG/100175467 You will be measuring the pressure after their regulator.

    An alternative would be that it was not their toilet, but was some other water device. That recording sure sounds like a toilet, however.
  9. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Hi Reach4,

    You are too nice to be true.

    I will go talk to my neighbors when I'm off work. It never occurred to us that the noise might be from next door, because it is so loud inside our own rooms. We can hear it everywhere upstairs.

    We have some hope now. Thanks again!
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    It is not uncommon for the water pressure to rise at night when fewer people are using any, and they are trying to refill the reservoir or water towers. A leaking toilet can make some weird noises when it tries to refill. A toilet fill valve in poor repair might start to leak when the pressure rises, and that excess would reach the overflow and other than wasted water, there would be no other visible damage or indication (other than possibly some sounds).

    If the building has a pressure reduction valve (prv), it could be in need of repair. WHen you have a PRV, the system also needs an expansion tank, and those can go bad. Without one, the pressure rise when the WH runs can be an issue.

    It might be an issue with the sprinkler pipes and valves with air or leaking.

    If you ever do figure this out, let us know, it will be one to file away.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,279
    Location:
    Cave Creek, Arizona
    Haven't a clue as to what could make that sound I once had a customer who told me they had a pump that ran every 10 minutes or so and it was driving them crazy. The problem was that they did not have a basement OR a pump. While trying to trace the source of the noise, I was listening on the floor to pinpoint it, when i went under the desk to listen. While I was there, the sound occurred, but it was above me. I opened a desk drawer and found a pager, set for vibrate. The battery was dying so it came on every 10 minutes as a warning to change the battery. The thin wood of the drawer bottom was acting as a resonator sending the sound all through the room.
  12. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Dear Jim,

    Thanks for the reply. In your first paragraph, are you suggesting that even though everything inside the toilet is new, it might still leak (if poorly installed) when the the pressure changes during the night? Is it easy for us to see the leak when the noise comes up?

    Please suggest what we can do to confirm. Thanks again for the help!
  13. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Dear Reach4,

    Just talked to all the neighbors in the same complex. None of them has heard the water/pipe noise recently. They don't shower or do laundry during midnights. They have not noticed any leaking in their homes recently. But they offer to listen up for us and will inform us if they hear anything. They are all very kind people.

    Looks like this is only happening to us. If the noise comes up tonight, I will go around and check on our toilets again (thanks for jadnashua's suggestion.)
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    If the new valve isn't defective, it's probably not a source of any leaks. But, I suggest you get yourself a water pressure gauge ($10-15 or so). Get one with a second, peak reading (tattle tale) hand, and leave it hooked up to your plumbing for a day or so. Note what your 'normal' pressure is, and what the peak pressure is. That might be revealing (or not). If the pressure ever gets above 80psi, that's one issue to address first then see if it solves your problem. If the valve was leaking, the water level would rise and then start running down the overflow tube. If it never rises, it's not an issue.
  15. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Hi hj,

    That is a very interesting story! I do hope that we are just having a "water pager" somewhere causing trouble and we can turn it off ...
  16. Reach4

    Reach4 Active Member

    Messages:
    1,917
    Location:
    IL
    Since the sound kept going when you had turned off your water and drained your pipes,I cannot see it being one of your toilets. I would get the pressure gauge.

    Put your ear against the neighboring walls where you think their bathrooms are if it happens. Maybe use the old water glass trick. [​IMG]
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    If the valve is still leaking, the water level in the tank would rise until it was going down the overflow tube. Probably not happening.

    Note, sounds can travel quite a ways in pipes, so the issue may not be in your unit.

    I'd go buy a water pressure gauge ($10-15 or so), get one with a second, tattle-tale, peak reading hand, then hook it up (maybe a washing machine supply, or the WH drain (careful, it can get hot), or if you have a hose bib, or nearly any faucet if you buy an adapter. Leave it on for 24-hours or so. Note the 'normal' pressure and the peak pressure. If either one gets above 80psi, then you need to address that, and that may resolve the problem. May not, but anything above 80psi should be addressed, regardless.
  18. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Hi Reach4,

    Looks like my earplugs worked, did not wake to the noise during sleep. Feeling better today. :)

    We are considering to try turning off the main valve again when the noise comes up. Because we did that experiment when the hammering sound was there (though turning off the main valve eliminated the hammering sound), don't know if things have changed after the pressure regulator is replaced.

    Hmm... We incline to trust our neighbors because we know that they sleep early and get up early (~5am).
  19. Jessicayiyi

    Jessicayiyi New Member

    Messages:
    11
    Location:
    California
    Dear Jadnashua,

    We will get a water pressure gauge as you suggested. Can we hook it up above the main valve? We saw the plumber did that (the number is always 60psi). Maybe there is a reason that we should hook it up somewhere inside our home?

    Thanks again for the suggestion!
  20. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    Except for a slight difference because of height changes, when you are not running water in the house, the pressure is essentially the same everywhere, so install it where it is convenient. FWIW, the static change in elevation is 0.433#/foot for water. So the pressure upstairs would be less than the basement when you were running it.
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