I find this really a problem when public service is pushed aside by private interest. The Drum Trap is a very bad design as it is purported to replace the standard p-trap under wash basins and bath tubs. Especially bath tubs where there is very little room underneath. The drum has a larger area so the incoming waste water is slowed down and hairs and other crud begins to collect and in a year or two it plugs up. By the time it plugs up the cap has seized up and hard to remove. It should be banned but plumbers love them as it is a big repair job and lots of money. It is a money pit and should be banned.