Replaced two toilets in a single level condo (both bathrooms are adjoining and the toilets are approximately 8 feet apart from each other) with Kohler Cimmaron toilets. I was having trouble with the OEM Mansfield toilets "completing" their flushes. Both new toilets gurgle substantially when flushed and I noticed today that when one toilet is flushed, the other toilet's bowl water moves around--not quite to the point of splashing, but just moving vigorously. We had a plumber come in and told us that the gurgling on both toilets is a common characteristic of these "Aqua Piston" flush Kohlers. I find that hard to believe as I've put them in just about every home I've purchased in recent years and never had this issue. I'd appreciate anyone's comments on whether the condo association needs to hire a plumber to either check my sewer lines for a partial blockage, or possibly the vent stack on a (very pitched!) roof.

I have an older model Kohler toilet that has the rubber flap. I replaced the rubber flap because the tank was losing water but that did not work. I tried cleaning around the pipe that the flap rests against thinking some sediment may have built up & not allowing the rubber flap to make a proper seal but the tank is still losing water. Can anyone suggest what to look for or do to stop this issue? thanks