The original Whirlpool garbage disposers installed @ The Vaux are not the most powerful available, and not everything gets chewed up thoroughly. Even when reduced to slurry, some forms of waste — starchy stuff, fruit rinds, coffee grounds — may still collect in the pipes. Run a lot of water in your sink after using your disposer! That's the lesson taught by an actual situation that arose in the Savier building not so long ago. In that case a plug of compacted waste in the drain below one unit caused water to overflow the sink in the unit above. Water then leaked back through the lower unit's ceiling. Both units sustained considerable damage. Ouch, that's expensive!