Pipe vibration noise really annoys

Hey there, time traveller!
This article was published 22/01/2011 (5368 days ago), so information in it may no longer be current.

Question: Approximately two weeks ago, a humming sound started in my two storey house. It starts out softly then increases in volume for about ten seconds and stops. After about 30 to 40 seconds it starts again. This cycle has continued for about a week now, but it has since started cycling faster.

The sound is emanating from the main cold water line in the house. Although the sound can be heard throughout the house, it is more noticeable in the main floor powder room and even louder in the main bathroom directly above on the second floor. If you feel the pipe that feeds the toilet, it is actually vibrating. Also, you can feel the sensation in the wall behind the toilet. There are no leaks in the system and if you run some water for about a minute the sound does not come back for a few minutes.

I have turned off the main water valve, opened all the taps to drain the lines then turned the water back on after about five minutes. This stopped the noise for about 20 minutes. So far, I have had a plumber and a city employee from the water department come but they could not determine what was causing this. Also, because the stack runs up the wall behind the toilet, I have had this cleared of ice build-up.

Any idea what is causing this and if so how do I solve it? Your advice would be appreciated.

— Arnold Guy

Answer: The answer to your dilemma undoubtedly lies outside the confines of your home, unless you have added any new mechanical equipment recently. While it may be hidden from view, there is something that is causing a vibration in the metal water supply piping in your home. It may be difficult to determine the culprit, but hopefully it will be something of a temporary nature.

When trying to diagnose the cause of difficult or hidden issues like yours, I always try to eliminate the obvious, first. I do this by initially enquiring about any recent changes to the building, contents, or components. If you have changed any plumbing fixtures, pipes or walls, this could easily affect the existing piping. Alterations to any of these items, even something as simple as replacing a toilet or faucet, may cause vibration noises if the new fixtures are defective or installed improperly. As well, large mechanical devices such as a furnace, dehumidifier, air cleaner, HRV, or others that contain fans may cause new vibrations in your floors or the metal piping. Kitchen appliances, specifically refrigerators, convection ranges or dishwashers, can also cause vibration noises. This can happen from movement from a fan, pump, or compressor contained within these appliances. It can also happen if a particular frequency of sound is emanating from these devices that happens to affect copper pipes. If you have any newer items of this nature, check them thoroughly to see if the pipe problem happens when they are in use and modifications may be possible to minimize or eliminate the problem.

If you have made no changes to your home or contents, the offending party must be located below grade or outside of your home. Until recently, the majority of outside underground water supply piping in our area was metal. Metal piping, especially copper or brass, is a very good choice for this purpose due to its strength, flexibility, and resistance to deterioration or corrosion. This type of underground piping may perform well for several decades without a problem, but there are some drawbacks to using metal pipes. Copper is an excellent conductor of electricity and heat and may be subject to significant expansion and contraction with quick changes in temperature. It is also prone to vibrate when banged or moved. This is rarely a problem for buried piping because the municipal water and ground temperature should be fairly consistent. This is true until something occurs that changes this normal situation and that should be the next area to explore.

If there has been any work done in the vicinity of your home in the last few months, particularly road or sewer work, that may be the answer to your problem, especially if it is still ongoing. If nearby buildings have had new water or sewer supply piping installed or repaired, the changes may have connected some other device or component outside you home that is causing the pipe vibration. I would expect that the city employee would have investigated this if it was a sewer or water issue, but that may not necessarily be the case if the cause is something entirely different. If there are any commercial or industrial buildings near your home, they may have recently installed some equipment that is causing the ground or the water supply pipes to vibrate. Determining that may be much more difficult, but if your house is located in a mixed use area, that is a strong possibility.

As I have stated in previous columns, noise related issues are among the most difficult to address in many buildings. Your noise problem is most likely due to a vibration in the metal water supply piping. The fact that the noise goes away after running the water for a few minutes is evidence of this. The force of the water running through the pipes when a faucet is opened should easily overpower the other vibrations, stopping the noise. Investigation to solve this problem may be tricky, but exploring any recent changes or construction inside or outside your home should yield the answer.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the President of the Canadian Association of Home & Property Inspectors – Manitoba (www.cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at (204) 291-5358 or check out his website at www.trainedeye.ca.

trainedeye@iname.com