A horizontal drain trap. What's wrong with that, you say? Not only won't this drain properly, but the slug of water that would sit at the bottom of the pipe, if it were installed vertically as it should be, would keep sewer gases from coming up through the drain. And the crud that will collect in that accordion pipe? Eeeww...
Thomas R. Battoe
Performance Home Inspections
DeBary, Fla.courtesy of the ASHI Reporter