Drainage, Waste & VentQuestion 76 of 360
The minimum trap and trap arm size for a lavatory is:
a.1-1/2 inch
b.2 inch
c.1 inch
d.1-1/4 inch
Explanation
A lavatory has a minimum trap and trap arm size of 1-1/4 inch and a DFU value of 1. A 1-1/2 or 2 inch trap is larger than required, and a 1 inch trap is smaller than the code minimum for any fixture. Kitchen sinks, by contrast, require a 1-1/2 inch trap.
Law Reference: 2022 California Plumbing Code (CPC) §702.0 (Table 702.1)Practice all 360 questions free — no signup required.
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