: I have the same Kohler toilets in 4 bathrooms. The bowl fills to differnt levels in each. Some are way to low for good wast disposal. What controls the water level in the bowl. can it be adjustedThe refill tube from the ballcock controls this level. normally enough water flows through this tube to fill the bowl back up to its trap level. this would make them all the same. check the tank water level in each toilet, if its too low and cutting off before it should. if these are old units the gaskets in the ballcock could be bad and blocking refill line. if there is a partical blockage in main line that could cause same problem