I have a newly constructed office that opened 3 weeks ago. The second day the toilet overflowed and was accompanied by water backing up into sinks. The plumber pulled 'paper towels' out of the line. The next week he said it was again due to 'paper towels' and changed to a high flow toilet. Yesterday it happened again. A camera showed paper towels (or white balls of some type of paper), and the plumber and building management are convinced we are throwing things in the toilet. The toilet is used by 6 adults who know better than to throw paper towels, sanitary napkins etc down the bowl. I do not doubt that paper is accumulating and causing a clog, but is it possible that the accumulation is because the system was improperly installed in the first place, leading to insufficient pressures? Thanks for your help.