Drainage, Waste & VentQuestion 99 of 360
The DFU value assigned to a single lavatory is:
a.2
b.3
c.1
d.4
Explanation
A lavatory is assigned 1 DFU, the smallest common value, with a 1-1/4 inch minimum trap. Values of 2, 3, or 4 belong to higher-discharge fixtures such as sinks, tubs, or water closets. Using the correct DFU keeps branch and drain sizing accurate.
Law Reference: 2022 California Plumbing Code (CPC) §702.0 (Table 702.1)Practice all 360 questions free — no signup required.
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