I recently put in a new bathroom on the first floor right below the old bathroom on the second floor. Since getting the new toilet, we've had two badly clogged sewer lines that has backed up into my basement. The clogs have been somewhere between the house and the the city sewer system in the street. Probably at my sidewalk p-trap/vent. Could a new toilet cause these clogs, or is it just coincidence? The old toilet used a lot more water than the new toilet so I'm wondering if that is the problem.