Dear Angie: Our two-story home has four-and-a-half bathrooms, which all seem to have a common cold water pipe that runs through a particular wall and ceiling. In four of the baths, when the toilet is flushed the water cutoff causes the pipes to vibrate very loudly somewhere in the wall or ceiling. Turning off the cold water faucet at the sink also causes a vibration. We’ve had three different plumbers out. They have cut through walls in two different rooms and failed to locate the section of pipe that is causing the problem. Is there a tool that a plumber could use to locate the problem area before cutting through the wrong area of walls/ceiling again? Or, is there another way that this vibration problem could be resolved? — Claire K., Nashville, TN.
Dear Claire: There could be a few different issues causing the rattling noise you hear in your pipes behind the walls, so that means there’s more than one option to solve the problem. Fortunately, none of them should be too invasive. To start, the problem could be a loose pipe, as you suggest, which would merely need to be secured to the wood framing with pipe clips. Ideally, this could be done by accessing the pipes via an access panel or open area where the pipes are exposed, like a basement, rather than cutting through a wall or ceiling. Visibly inspect your pipes in open areas to see if there is a lot of movement when someone in the home turns faucets on and off or flushes a toilet.
Another issue could be that your water pressure is too high, which can cause pipes to vibrate and also lead to long-term damage to your pipes and appliances. Highly rated plumbers I’ve spoken to in your area say the indoor water pressure should be between 40 and 60 pounds per square inch (PSI). Adding a pressure reducing valve to your incoming main line could correct that issue, if high pressure is your problem. There are water pressure test gauges you can purchase to test the pressure yourself, or a qualified plumber can test your pressure for you.
Finally, a common occurrence known as a water hammer could be what you’re experiencing. A water hammer is caused by fast-closing valves, like toilet fill valves and faucets. As the water flows through the pipes and the valve shuts off quickly, it causes the water to stop suddenly in the pipes, causing the “hammer” effect. Adding a water hammer arrestor to the offending pipes could correct this issue, but that can involve cutting and soldering pipes and would likely require the experience of a plumber. Again, ideally, the plumber could add the arrestor to the pipes where they are already exposed without cutting through drywall. One possible simple solution to water hammer could be to replace your toilet fill valves with slow-shutting fill valves.
If you’ve lived in the house for a long time and the hammering effect has gradually gotten worse, it could be that you have air chambers connected to your pipes behind the walls. Air chambers help cushion against water hammer, but they fill with water over time and need to be drained allow them to refill with air. This can be done easily by most homeowners by shutting off the water main valve, opening up the faucets and flushing the toilets starting at the highest level of the home and working their way down to the lowest level until all the pipes have drained. Once the lowest pipe runs clear, close that drain and turn the water main back on.
The noises you hear can not only be aggravating, but could lead to a pipe breaking because of the force of the banging. Water damage can be devastating and expensive to repair, so you want to be sure to find a well-reputed plumber in your area to help diagnose and treat the problem.