Why won't the water level stay in the toilet bowl?

Answer 1

If water is leaving the bowl then there could be a couple of solutions. There could be a partial clog in the sewer lines or vents, causing a vacuum that draws the water out. Cleaning out the lines will fix this. Or the bowl could have a small crack, which will require a new toilet.

Answer 2

vent

1- blocked vent

2- missing vent

3- negative pressure

4- positive pressure

Stoppage

1- Something may be in the crown weir of the toilets trap causing capillary action thus draining the bowl contents and weakening the trap seal

Mechanical

1- The refill is not properly installed

2- inadequate volume

3- A Kohler product (IMHO)

Alternative perspective from a non plumber:

I had the same problem. I replaced the flapper with a red Korky flapper and replaced the rubber flange at the bottom (inside) of the tank that the flapper marries with to create the water seal. No more leaks for me. Those things just deteriorate after several yrs.

Almost every time I have seen the water level in the bowl decrease, it has been on account of a mostly (not completely) clogged sewer line. Very often, this decrease in water is accompanied by a kind of burping or bubbling in the bowl.

Answer 3

If the water is decreasing from the tank, check the flapper at the bottom of the tank. Press it gently downward. If the leak stops, you can get a new flapper cheap.

If the water is lowering from the bowl, re-check all fittings inside the tank, especially around the handle. You may need to adjust the float, but many times, the flush handle is or chain going to the flapper have a problem.