Where is my toilet leak?

[Donn2390]

You solved my Toto problem last month, now I'm on to bigger and better things.
I have two standard builder grade toilets that I recently changed all of the parts in the tank. One had a slow leak, the other was the same age and looked grimy, so I replaced all the internal tank parts on both.
Both toilets are still leaking. I assume it has to be leaking at the flapper because there are no external leaks, no water on the floor, etc.
Our home has four bathrooms, two with Totos, two with the builder grade, installed around 2002. Two people live there so the two problem toilets are always turned off. I am now renting the home out so I want all four to work perfectly.
With the new internal parts installed, I fill the tank to the shut off point, and then turn off the valve. In a 24 hour period, the level will drop about an inch. Not very much, but more than I like to see.
I purchased the Fluidmaster kits which I assume are the gold standard. I am at a loss to figure out where and why I'm losing that water.
I live in the California desert, where water is precious and expensive, it's not uncommon to see water bills of several hundred dollars a month, 3-4 hundred dollar water bills are common, so every drop adds up.
I've been fighting this for weeks now, so discouraged I'm about to go buy two more Totos...!
Suggestions??
Thank you....

 

[Reach4]

Feel around the seat that the flapper mates with. Ideally you will detect debris, and will wipe it away.

Make sure there is not tension on the flapper from the chain.

If the water level does not continue to drop after that inch, it is rare but possible that the overflow tube has a crack.

If the little tube from the fill valve goes down the hole a ways, that can siphon out water into the overflow. Usually there is a little clip to hold the tubing up.

 

[Sponsor]

 

[Donn2390]

I left here Sunday afternoon and just returned home late this afternoon, Wednesday. The water level was just at the bottom of both floats after three full days, so the seep is slight.
I believe I tried those suggestions already, however I just double checked both the flapper and the seat for any debris, which appeared to be clean. I even pushed the flapper up and down on the seat to make sure it is properly seated. The chain is adjusted properly, no problem there.
I refilled the tank and turned off the inlet valve, so I'll see how it looks tomorrow morning. I suppose losing an inch or so over three days isn't a big deal, but it is to me...
Thanks for your suggestions...

 

[Jadnashua]

With the lid on, it shouldn't be evaporation.

It's possible that it's leaking around the spud nut...the part that holds the flush valve to the tank. If it leaks there, it might just go down the drain without leaking anywhere you'd see it...it's going down the drain. SOmetimes, all it takes is snugging up that nut, but you must remove the tank first.

 

[Donn2390]

With the lid on, it shouldn't be evaporation.

It's possible that it's leaking around the spud nut...the part that holds the flush valve to the tank. If it leaks there, it might just go down the drain without leaking anywhere you'd see it...it's going down the drain. SOmetimes, all it takes is snugging up that nut, but you must remove the tank first.

OK, in my quest to leave no stone un turned, first thing this morning I ripped off both tanks and tightened not only the spud nut, but the two mounting bolts as well. I tightened both spud nuts, one a little, on a lot, and reassembled them and they are now in the test mode, which unfortunately takes a period of time.
I have great confidence this is going to do the trick, as not much else could be wrong, everything but the tank it's self is new, and everything is now tight. I will see what happens tomorrow.
Thank you for the suggestion....
gb

With the lid on, it shouldn't be evaporation.

It's possible that it's leaking around the spud nut...the part that holds the flush valve to the tank. If it leaks there, it might just go down the drain without leaking anywhere you'd see it...it's going down the drain. SOmetimes, all it takes is snugging up that nut, but you must remove the tank first.

OK, in my quest to leave no stone un turned, first thing this morning I ripped off both tanks and tightened, not only the spud nut, but the two mounting bolts as well.
I tightened both spud nuts, one a little, one a lot, and reassembled them and they are now in the test mode, which unfortunately takes a period of time before I will know for sure. It can only be better, right??...!!
I have great confidence this is going to do the trick, as not much else could be wrong, everything but the tank it's self is new, and everything is now tight. I will see what happens tomorrow.
Thank you for the suggestion....
gb