I've seen some other questions about dripping sounds but wasn't sure if my situation fills the same circumstances or not.

I have a 2-story home and only a partial understanding of where the mechanisms of HVAC and plumbing are run.

In a wall that is nowhere near the exterior walls of the home, we're hearing a intermittent dripping sound and yet not seeing any damage (yet) nor would we prefer to wait for visible damage before addressing it.

The wall/ceiling where we hear the sound is near the upstairs shower/tub combo. There is an access panel into the back of the tub and yet when we listen there the drip sound is not audible nor is there anything obviously/ominously wrong to my eyes -- despite being roughly in the same location.

I've heard and read on this site that warming/cooling hvac or plumbing runs can produce this "drip-like" sounds so am hopeful for this outcome but don't know how to confirm.

We've lived here for 5 months (starting in the heat of summer) and only noticed this sound in the past 3 days in the beginning of Winter -- but our heat has been running off/on for a month or so.

Before we heard (noticed?) the sound, we turned off the water to install a new valve fixture on the first floor. Did something shake loose with the sudden change in the status-quo of the normal, pressured environment?

What contractor can tell the difference between normal water dripping inside a pipe versus outside versus condensation versus rubbing sounds of metal on wood? Who would you call first? A plumber or HVAC or "handyman"?

I've tried to isolate by closing drains on sinks and shutting off water to toilets but still haven't figured out what could stop the sound / behavior.

Thanks for your thoughts and perspective!


It still isn't clear to me the right kind of contractor to confirm what I found, but during periods of inactive furnace activity, the sound seems to die down. Also, when I place my ear next to the cavity (firmly against the wall) the sound transforms from dripping to ductwork creaking / popping and I can hear the sound of air being moved.

I'm hopeful that there is nothing to it and that I can come to peace with the red herring sound. My ambition will be to present this as the answer to my question if an HVAC person can confirm it unless someone else can recommend something better. Thank you.

  • one tip to figuring out your plumbing- if you have an unfinished basement, you can check the basement ceiling for a general idea where vents/pipes/sewer go up to the second floor. Nov 12, 2018 at 22:22
  • could be the shower drain ..... normally the water would run down the pipe walls .... but if there is a wad of hair extending into the vertical portion of the pipe, then the water could be dripping from the end of the hair wad and hitting the pipe further down
    – jsotola
    Nov 12, 2018 at 22:52
  • When you drain that tub, do you hear water rushing down that same spot in the wall? Does the dripping eventually stop, say in the morning before that bath is used?
    – Gary Bak
    Nov 13, 2018 at 12:49
  • Thank you everyone for your thoughts. We are on a slab @RobElliott; that makes sense to me jsotola and Gary. I captured all the dripping water from the tub and the next morning still heard some sounds. After resting my ear against the cavity, I have come to convince myself that the sounds are eerily similar to hvac duct metal grinding/popping but somehow an inch away my ears interpret it as water dripping. Is an HVAC person the right person to hire out?
    – veeTrain
    Nov 13, 2018 at 13:40
  • Maybe you can attach some kind of ear piece to the air ducts and see if it's more noticeable...
    – rogerdpack
    Apr 20, 2020 at 4:17

2 Answers 2


You could have an HVAC condensate drain that is dripping into a vent stack pipe for your waste plumbing. They (HVAC installers) are not supposed to do that, the condensate drain is supposed to run to the outside of the house in a dedicated line. But I've seen several cases where that was not done and the lazy HVAC contractors just put a Y fitting on a nearby vent stack and run their condensate drain into it. There are potentially serious problems with that because sewer gasses can get sucked into the HVAC system. That's why waste vent pipes extend all the way up to the roof.

  • Thanks J.; this wouldn't be relevant if the condensate drain and furnace in general are 30 feet away, right? The AC condensate I know goes to a tiny pump which wouldn't be operating in the heating season, right? Thanks for sharing your experience
    – veeTrain
    Nov 15, 2018 at 19:00

Yep, it could be a leak or it could be condensation and it may not have been happening until the bath valve was replaced.

Meaning, the old valve may have been well sealed by a good gasket (full circumference), caulk or just years of built-up crud. Now, that's gone and the new valve with no seal at the very bottom (crappy gasket) that let's air and humidity into the wall to fuel condensation.

Therefore, check the valve upstairs isn't leaking and its escutcheon plate on a, possibly, shared stud-bay is sealed and correct any gaps or openings on the new valve. You may need to seal the escutcheon to even the new valve's handle.

On the other types of leaks that aren't leaks. Maybe the toilet upstairs needs a new Flush Valve Washer or Flapper to stop a drip. Or, maybe your sink or shower trap has hair in it that's literally wicking the trap dry.

Those, do very well explain a drip noise that causes no damage or moldy smell. Because, you're hearing the drip that's happening inside the drain pipe as the drop hits a pipe elbow.

You can even check the attic or basement/crawlspace (if applicable or accessible) for open holes that need sealing to stop humidity or warm air from being introduced into the wall. Water may have leaked during valve replacement and flushed a hole clear in the basement/crawlspace.

  • Buy or rent an inspection camera from your local big box. These tools have small screens on them with a probe that has a camera on the end. You drill a 3/4" hole in the drywall, insert the camera and see inside your wall. The probes are bendable and some models have a 6-foot extension for the probe length. You might be able to identify wet areas, drips etc. This way. The cameras range from $39 to $429.
    – DAS
    Jan 18, 2021 at 8:21
  • Great idea, I've never used one...but, I've heard good things. I hope they come back with the answer someday.
    – Iggy
    Jan 20, 2021 at 14:37

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