Kohler toilet makes leaking sounds, but never refills

[BigCanoer]

I've searched the toilet forum looking for a similar problem to mine, but I did not see any posts about a toilet that makes leaking sounds but the tank never refills with water.
I installed a new toilet in our 40-yo home right after we moved in two years ago, and ever since we have noticed faint dripping sounds that come from (apparently) below the toilet.
I put a few drops of food coloring in the tank to see if the leak is coming into the bowl, but no dice.
I turned off the water supply completely to see if that made any difference, and sure enough, the dripping sounds stopped -- and the tank water level never decreased.
So after leaving the water supply off (to ponder and repair when I had more time - ha) it's been more than a month ... and our most recent water bill was tremendously lower than it has been for the past two years. Could this leak that I cannot locate have been responsible for an extra 150 gallons of water per day? If so, why did we never hear the toilet refilling?
I am far too frugal to hire a professional, but I may have to if I cannot resolve this on my own.
As it stands now, I emptied the tank, removed it and have it sitting in my guest bathroom floor while I search the web for a solution to my leaking-but-never-refilling toilet.
New parts, maybe? If so, which one(s)?
The toilet is the troublesome Kohler brand with the triangular rubber gasket beneath the tank, and the canister style valve assembly in the tank (ugh).
Suggestions are welcome. Thanks.

 

[Reach4]

I put a few drops of food coloring in the tank to see if the leak is coming into the bowl, but no dice.

Food color is not so intense that a leak would color the water noticably in the bowl when diluted. Instead you could have put the food color into the tank and see if the color intensity reduced overnight.

I turned off the water supply completely to see if that made any difference, and sure enough, the dripping sounds stopped -- and the tank water level never decreased.

You turned the water off at the stop valve inside the bathroom that feeds the toilet? If yes, then something with the toilet would be the problem. If you turned off the water in the basement, then there could be a leak in a wall.

and the tank water level never decreased.

That vindicates the flush valve.
I am presuming that the dye test was not adequate. So the choices are the fill valve and the fill valve being set too high, letting water go down the overflow. If the water level is close to the top of the overflow tube, the water may climb the clip by capillary action. If the water level is 1/2 inch below the overflow, that would probably not happen. Temporarily removing the refill tube clip and letting the water go into the tank would be a test. That will cause the bowl to not refill after a flush, but you would only have the clip off while you are testing.

 

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[BigCanoer]

Thanks for the responses!
Per your question above, I did turn off the water at the toilet stop valve, not the water main.
I will put the tank back on and test the fill valve to see if it is set too high -- I was not aware that water could climb the overflow by capillary action. Muchas gracias!

 

[WJcandee]

When you turned off the water at the wall, the tank level did not fall at all? Did you do a "leave it overnight" turned-off test? Did you make sure the refill hose is daylighted above the overflow tube on a little clip? I'm guessing that it's the flush valve, or the refill hose stuck down the overflow.

Test by turning off water at wall overnight. If tank level doesn't fall, then you're not putting 150 gals/day through the toilet.

150 gallons per day is a lot. That's 100+ flushes worth. You would see evidence of that.

 

[Reach4]

Did you do a "leave it overnight" turned-off test?

I thought she was saying she left it for a month.

 

[Elizabeth Franke]

What was the solution? I have had the same problem. Can't figure out where the dripping noise is coming from and going to. This toilet is a fully skirted style and requires a trapway (?) to be installed and bolted to the floor before the toilet is then lower over it and in place.

 

[WorthFlorida]

What was the solution? I have had the same problem. Can't figure out where the dripping noise is coming from and going to. This toilet is a fully skirted style and requires a trapway (?) to be installed and bolted to the floor before the toilet is then lower over it and in place.

As what I gather it apparently was the tank water level was too high. The water level needs to be an 1/2" or so below the overflow tube. Reach4 had a good explanation. Depending on your Fill Valve, they are all adjustable but could be different with different brands.