In the last few days our toilet bowl water level has dropped to 1/3 of the normal level. When flushed water stay at old level and with in few seconds it drops to 1/3. There is no water leaking on the floor. Any idea what is the problem:confused:

There are several things that would cause this problem. (1) A crack in the bowl that can't be seen,**or** (2) Sometimes a bubble will occur in the casting that causes a hole that allows water to leak back down into the closet bend and out into the sewer. Instead of junking the bowl the manufacture will float a porcelain patch over the hole. Sometimes this patch comes loose and the bowl loses water. A blocked vent could cause a lowering of the water level but this almost never happens. You would hear a gurgle in fixtures with lesser traps first. Regards, Tom

Thanks Tom, I can hear a burble sound after water going through the bathroom sink too. But this is only happening in the last two days. Where is the vent located and what is the fix for path problem.