Hard to describe so I made a video. The noise happens about every 25 minutes.
[www.youtube.com]

Not enough info and hard to diagnose from here. Has this always been an issue or started recently? Has any plumbing fixtures/repairs been changed lately?
Do a food dye test in all your toilet tanks and see if it leaks into the bowl. Post back with results.



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My hot water tank makes this pressure relieving noise about every 25 minutes. Actually, I think it's the smaller tank at the top of the bigger tank... I replaced the hot water tank after this issue continued and I walked in my garage and it was really humid and warm inside and my kitchen flooded.... on my 2nd tank now... not sure if it has to do with the toilets. the issue started a few months ago and the noise becomes more and more frequent.



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have you recently purchased a new appliance?

The tank is new. But I don't think that is the problem.



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does air or water come out of that smaller tank? Don't forget to put the air back in if you release air.(oops on the top should be a schreador valve ((tire type air fill valve)) what comes out of it if you depress it?? but put the air back in if air comes out and replace the tank if water comes out

I'm guessing air comes out because I never see water leaking... which one is supposed to come out? How would I put air back?



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air should come out... if you give it a quick press on the tire filler like thingy up top. if too much air comes out you will need a tire pressure guage and a bike pump orcompressor to replace the air that maintains that pressure. a little press to see what comes out may not need to be replenished, and if too much comes out there should be a a sticker on it saying what the air pressure should be. so if air comes out , the problem is elsewhere, if water comes out- start by replacing that little tank

Oh yeah the plumber tested the pressure and it was off the charts. Quoted an astronomical Price and said something about having to take out part of the ceiling

You need a pro plumber. Period.

What is your house regulated pressure? I made refrence to the toilets simply because the noise you refer to seems associated with the cold water side of the W/H. A leaky flapper valve OR a fill hose that is too long can cause siphoning/filling to occur every 25 minutes or so.

You say the expansion tank has been changed 2 times, the garage is moist, the whooshing sound occurs every 25 minutes, a plumber said your pressure is too high and your kitchen flooded

CALL A PROFESSIONAL LICENECED PLUMBER.



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Probably a toilet tank refilling, and the tank is acting as a resonator to amplify the sound.

DON'T do it. Nothing in that tank could make a noise, especially a recurring one.

quote; Quoted an astronomical Price and said something about having to take out part of the ceiling

What do YOU consider to be an "astronomical price", and WHY would he have to take out part of the ceiling? If what you say is true, then you did not have a "plumber" or at least not a competent one.