I am trying to locate the source of some odor in my bathroom. It is a "3/4
bath" and I suspect the odor is coming from the shower drain. I cannot see a
"trap" in the plumbing draining the shower (in the parts I could actually
visualize). Does plumbing draining a bathtub or shower have a trap like a
sink does? If it doesn't, does it seem reasonable this could be the source
of the odor (smells a little sewery)? The house is about 20 years old.
Thanks!

Boatman