I have two bathrooms back to back in my new store. When I flush one toilet it sucks water from the toilet bowl of the other. How can this problem be corrected?

John

I'm assuming you picked up the toilets with a double sanitary tee or a double combo. There should be a vent through the roof coming out of the top of the fitting. If you vented the back to back toilets correctly there shouldn't be suction from one toilet to the other. My advice? Check the vent. Regards, Tom

Change to a bowl that has a deeper trap.
[just kidding]
Call the inspector from the permit you pulled and have him come look at it. Being a new store something will be changed quickly.