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Fog horn sound

We have an intermittent fog horn sound in the wall in our first floor. We can hear it throughout the house and even outside, but it is loudest on the first floor, between the laundry room and the bathroom. We have tried turning off the A/C, turning off toilets, etc. We can't pinpoint what is causing the sound. It appears to be random-not associated with running water, lasting for 15 seconds every 5 to 10 minutes.

This started last night and I'm not sure we are any closer to knowing what is causing it. It isn't related to an A/C turning on, or any faucet, washer or toilet being used. We have turned our water heater to vacation setting, but that hasn't helped yet but we only did this a few hours ago.

Is there anything else we should try?

Thank you for the help.

Re: Fog horn sound

Does it happen every day? More when its windy outside?

Re: Fog horn sound

I'd check the refrigerator. Sometimes the fan makes mysterious sounds.

If it's not the refrigerator, it's the IRS.

Re: Fog horn sound

This noise is known as "foghorn" or "water hammer" noise and can have several sources; but the most common is the 1) fill valve inside older toilet bowls, sometimes combined with a leaky flush valve---what happens in this case is that a washer at the top of the fill valve gets worn & begins to vibrate producing the noise as the pressurized water supply fills the tank after a flush----if the flush valve is also leaking, the tank will gradually empty to the point where the refill valve is tripped on periodically, and the "foghorn" sound continues periodically----and a lot of water is lost over weeks & months, costing big $$$.

Another possibility is 2) a defective pressurized water supply shutoff valve line going into the base of the toilet bowl---if the valve washer is worn in this fitting, you will hear the same effect.

Less likely is 3) an air-eliminator valve inside the wall that automatically removes air from the water supply lines & has become defective, also by a loose, worn washer.

Another possibility 4) is, as Houston Remodeler suggests, a small roof vent with a metal flapper valve that is "humming" whenever the wind blows; and also, dj1's suggestion of a refrigerator fan.

I would suggest you first try to isolate the source of the noise to a specific part of the house, or a specific fixture, by taking a 6' length of black clothes washer hose, or similar hose; hold one end up to your ear, & point the other end toward the suspected sources of the noise whenever it occurs---eventually you will be able to pinpoint the location of the noise to a particular location---almost any type of flexible hose can be used for this procedure; you can also try to hold a solid metal or wood tool such as a hammer or large screwdriver against the wall (if this is where it seems to come from) and press your ear against the tool as a noise locator; but if you don't succeed in isolating the source of the noise to a particular location, you'll get nowhere & go nuts running around in circles.

If it turns out to be the toilet, check out the site below for illustrations & diagrams of various toilet tank parts as a guide to your repair-------note at the bottom of this site, when you get there, that you can click onto Pages 1 thru 8 to get various diagrams & fix-it tips for toilet water hammer repair; also note that they describe one of the symptoms as "toilet whines while filling".


Re: Fog horn sound

Most likely the fill & flapper valve in the closest toilet needs to be replaced. Replacing just the flapper may help.
The flapper is slowly leaking and when the water level goes down, the fill valve opens slightly and it starts to vibrate as water flows past.
When the fog horn starts, flush the toilet & see if the noise stops. That's your culprit if it does.

Re: Fog horn sound

I :cool:like Ed's idea best

Re: Fog horn sound

Ditto for Ed's answer!

I've dealt with sound this several times and it was always the toilet. I take a different approach than many when it comes to toilet work. If anything inside the tank needs repair, I like to pull the tank and redo everything while I'm in there with good quality parts (not the cheapo stuff going on sale this week at the big-box stores). That way I am not going to have to work on the toilet for many years to come, and when the tank needs to be removed again in 20 years the nuts and bolts that hold it (which will now be brass) will not be rusted in place. Done once and done right, the difference in money is chump change even to someone as frugal as me.

The difference in the time I can now spend watching TV instead of fixing things is priceless :cool:


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