I've been reading about the proper way to vent a utility sink in the
basement. After looking at the existing plumbing I discovered that a
first floor bath and kitchen sink share a single (wet) vent. Only the
bath sink has a dry vent. I bought this house (new construction) in
1992. All the plumbing books say that every fixture must have its own
vent, yet clearly this is not the case and it passed city inspection.
Since this configuration has not had any problems since 1992, I'd say
it works just fine but not to code. Is this a common occurrence? Are
there any perfect plumbing systems?