I have a toilet that will start running as if the flapper is bad. (I’m confident it is not. I’ve replaced it twice.) It doesn’t drain much, just enough to trigger a fill every 20 – 30 minutes.
The strange thing is the tank only drains slightly and then stops. If I turn the water off it will only drain approximately 1/4 to 3/8’s of an inch and then stop draining completely. I can leave the water turned off for two weeks and it will never go below that level. I’m thinking if it were a bad seal it would drain completely after that time.
Is it a crack in the tank? I’ve just about had it and ready to replace the toilet. It’s approximately 20 years old.
Best Answer
If the fill hose/tube (the hose/tube that runs from the fill valve to the overflow tube) is inserted into, rather than clipped above and aiming into, the overflow pipe, siphon action will lower the water level in the tank down to the distance the fill hose/tube is inserted.
Ensure the fill hose/tube is not inside of the overflow pipe below the normal water level.