Drainage, Waste & VentQuestion 87 of 360
A vent must rise vertically to a point above the flood-level rim of the highest fixture served before it may offset horizontally, by at least:
a.At the flood-level rim
b.3 inches above
c.6 inches above
d.12 inches above
Explanation
A vent must rise to at least 6 inches above the flood-level rim of the highest fixture served before offsetting horizontally, so that any drainage backup cannot enter the horizontal vent. Offsetting at or 3 inches above the rim risks fouling the vent, and 12 inches is more than the code minimum.
Law Reference: 2022 California Plumbing Code (CPC) §905.0Practice all 360 questions free — no signup required.
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