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Plumbing in the Home/groaning fog horn sound when water is turned on


Whenever we turn a water faucet on in the house we get a loud groaning sound almost like a muted fog horn sound that continues until the water is turned off. If another faucet is turned on at the same time the groaning sound will stop or the sound will be greatly reduced. Its not a hammering sound or banging sound but more like a muted fog horn. The plumber said we have normal city water pressure coming into the house, but couldn't determine the reason for the continuous loud noise whenever the water is turned on. It's happens with all the inside faucets when using hot, mild, or cold water.

Hi Jim,
A number of different things could be causing this. The most likely is a faulty pressure regulator. A weak spring in the regulator will allow the diaphragm to bypass and chatter under low flow conditions. That's why it reduces or stops when you turn on another faucet. You have effectively increased the flow rate.  It could also be a toilet fill valve doing the same thing. When you turn on the faucet, you momentarily drop the pressure in the system and it's the pressure that keeps the valve closed. I suspect it's probably the pressure regulator.
Good Luck,

Plumbing in the Home

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Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


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