Had toilet "insides" changed out (New flapper/valve etc). The toilet after being flushed will have a ringing (dripping) sound about 5 min or so afterwards. Turned water off for several hours and all the levels were the same.
Someone told me it makes the noise because it was put in the 1970's when they used copper drain? And something about the water coming into the toilet bowl and equalling itself out and drips back into the drain and hits the copper making this noise. Is that about right?

Thanks

That does not sound right. Do you hear the dripping sound if you flush and then shut off the water immediately after the tank fills?

In simple terms,

Never heard such a thing, nor does it make any logical sense.

When a toilet is flushed, the water in the tank flows (rapidly) from the tank to the bowl. This rapid addition of water to the bowl caused the bowl to flush and empty due to a siphon action. The flush valve closes due to the emptying of the tank. The lowering of the float causes the tank to refill. The flushing action in the bowl and the refilling of the tank are two separate actions.


Granted a small amount of water falling down a vertical pipe and hitting a horizontal section pipe could make a dripping sound. The only way that could occur in a toilet, is if the water level in the tank is to high and a small amount (very small) of water is flowing into the overflow pipe to bowl. This could cause a small amount of water to pass over the bend in the bowl trap and then down the sewer pipe.

All this amounts to, the water level in the tank should be about 1" below the top of the overflow pipe when the fill valve shuts off.

[QUOTESomeone told me it makes the noise because it was put in the 1970's when they used copper drain? And something about the water coming into the toilet bowl and equalling itself out and drips back into the drain and hits the copper making this noise. Is that about right?][/QUOTE] Either send that Dude back to plumbing 101 or let me has some of the stuff that he's smoking.
Follow Harold advice and shut the water off at the angle stop. Now flush the toilet. Do you still have the sound? Is it a dripping or a ringing? Answer me and we'll go from there. Back to you, Tom
P.S. Which ballcock is yours?

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The brand new one is the one on the left -- The old one on the right was like the original. The flapper and valve were replaced. So toilet has the new on the left. I think the overflow tube is still th same. Two different people who listened -- one thought it was a "drip sound" other said more high pitched. There is no continuous water leaking (which was the original problem and reason for doing anything -- high water usage & so very high water bill -- so changed the flapper and the other thing while at it.

Did you have the sound before replacing the fill valve and flapper?

Another source of a small leak could be between the overflow/flush valve assembly and the tank. To diagnose, put some food coloring in tank, wait some time and see if water in bowl changes color. If it does either the flapper is leaking or water is leaking between the overflow assembly and the tank and is causing a small drip into bowl.

It's in an upstairs bathroom that is seldom used. Did notice there was a "sound" after flushing when trying to figure out why water bill so high. Sort of sounded like a "drip" or ping - maybe copper would applify the sound? We decided the flapper was the cause and changed that and the other today. Still after flushing makes that sound for a few minutes -- then after 5 or so minutes nothing. Thanks for the idea --will check out the food coloring.