I need to move the drain under my bathroom sink -- It comes out of the floor and the new vanity has a drawer that extends across the entire bottom. I've figured out a couple of ways I might handle that, but I was trying to discover whether it is OK to put a turn in that pipe just at floor level. I guess that is actually question #1. The BIG question though is this: In looking at my plumbing book, I don't see any set-ups like mine. The trap for the sink clearly goes into a drain pipe that drops straight through the floor. I imagine there is a drain pipe running across the whole back of the house where all the other drains tie in. The drain pipe comes up from the floor 12" then has what appears to be a cap for a clean out. About 3" above that is a T that goes to the trap. About 24" above the floor the drain pipe ends with a cap that has a hole in it -- The vent I assume. All the sinks seem to have the same basic set-up. When I run my washing machine I always smell the detergent in my bathroom -- not bad, but I've been curious about it, and I assume this set-up is the reason. Is this an acceptable venting system? This is a manufactured home, built in 1989 and placed on a permanent foundation in 1999.