Hey Tom it seams you have some good answers to the same problem I am having but my house is new and all 7 bathrooms are full baths. 2 bathrooms are low on water level when they flush, the bowl stays with 3 inches of water. On the same floor I have 2 more bathrooms, those are keeping a good level of water... perhaps 8", I have two vent stacks on the second floor, three bathrooms are sharing one 3" vent stack, the other 1 shares another 3" with a 1st floor bath and a laundry... Why am I having the problem on two of the three bathrooms.. BTW all water levels were preformed before I set them and held water perfectly, not one drained an inch...

Tony

Hi Tony and Welcome to The Plumbing Page. At AskMeHelpDesk.com. You're responding to a 2 year old dead thread so I gave you one of your own. Look in then upper left hand corner of the first post form the date before you post, Thanks,
The depth of water in your toilet bowl is set by the shape of the internal trap of the toilet and the additional water the ballcock sends down as the tank fills. Are all bowls the same brand? Regular or elongated? I have two toilets, a regular and a elongated. 5" depth in the Kohler regular bowl and
6" in the Briggsw elongated bowl. 8" sounds high to me. Are these all the same brand? Any handicapped bowls? Any more information you can give me? Back to you, Tom