Hi there,

I have a situation that popped up a couple of weeks ago in which there appears to be a knocking/vibrating sound coming from the pipes that feed each of our two bathrooms. What is particularly strange is this sound occurs at the same time every day (around 12:40 p.m.) and lasts on and off for about 20 minutes. There is no water turned on in the house when this occurs. It starts up like clockwork and each episode lasts only about 20 seconds. From afar, it sounds like a deep knocking. If I press my ear to the wall, I can hear what sounds like the pipe vibrating. The hot water heater is in the garage on the other side of the wall from one bathroom, but the noise is much louder inside near the showers in either bathroom. Any suggestions?

Thanks,
Tony

Do you have a water softner, if so, how often and when does it regenerate?

Hi ballengerb1,

Thanks for the quick response (although I cannot see it in the question discussion thread; I saw it on your profile page). We do not have a water softener, although we are in the Phoenix area, which is notorious for hard water. I hope that helps somewhat.

Thanks,
Tony

Hi ballengerb1. Thanks for the quick response. We do not have a water softener, although we are in the Phoenix area, which is notorious for hard water. I hope that helps somewhat. Thanks, Tony

Have someone else help you by going around the home and open/close each faucet and valve. Sounds to me there is water being drawn and a washer is vobrating Could be something automatic, that's why I asked about a softner.

My first thought was the water softener also, Bob.

My next guess was a leaking flapper. Tony, take some dark food coloring and drip 10-15 drops into the toilet TANK(s) only and then wait an hour to see if the color shows up in the toilet BOWL(s). If colored water shows up in the toilet bowl then the toilet FLAPPER will need to be replaced to stop the water from slowly dripping into the bowl which would cause the toilet fill valve to have to SLOWLY replace the water lost which could be causing the sounds you hear at night... maybe?

If the flapper is the issue, why don't you hear this noise during the day? Most likely because there is just so much going on during the day that it goes unoticed... maybe?

Anyway, try the dye test and see what happens.

Otherwise, another test that you could do would be to shut off the main water supply to the house at the water meter (or pump), discharge the pressure from a faucet and then see if the sound returns that night. Either way, let us know what you discover, OK?

Mark

Do you have a lawn sprinkler or irrigation system with a timing device (even though it is shut down for the winter)?

Thanks everyone for their initial suggestions. To Hkstroud's question:

We have both a sprinkler and drip system. The sprinklers are shut off, but the drip system is active (although not at the time of the vibrations). The pool pump is running during this time, but it does so for a lot longer than this recurring thumping/vibrations. What's the connection to the pipes inside the house?

We'll check the faucets and valves, ballengerb1, and see if we discover something.

We'll also test the flapper, Mark. Thanks for the suggestion. Just to clarify, this is occurring around lunch time, not at night. I hear it on days I'm working from home (the den sits between the two bathrooms). Always the same time and for short bursts and for just about 20 minutes, which is why I too thought it may be related to something automatic.

Noise will travel a very long distance through water and the pipes. A pump or a valve opening and closing rapidly can cause water flow to rapidly start and stop. This can cause pipes to vibrate or to bang against structural members. I would look in that area for a source of the noise. Maybe change any timing schedules if possible.

Is it's duration 20 seconds or 20 minutes?

Interesting. The thumping/vibrating goes on for about 20 seconds at a time with short durations of silence in between. The noise stops altogether after about 20 minutes.

Hi Everyone,

Problem solved. We narrowed the problem to an irrigation valve that appeared to be trying to operate a valve that doesn't exist. Our timers got screwed up somehow. Anyway, we reset the timers to coordinate with the correct valves, and we have not heard the sound since.

Thanks to everyone for their suggestions.

Best regards,
Tony