Drainage, Waste & VentQuestion 71 of 360
What is the maximum number of water closets permitted on a 3 inch horizontal fixture branch?
a.1
b.3
c.2
d.4
Explanation
A 3 inch horizontal fixture branch is limited to a maximum of two water closets regardless of its 20 DFU capacity. This restriction exists because a 3 inch line cannot reliably carry the surge from more than two closets. Three or four water closets require a 4 inch branch.
Law Reference: 2022 California Plumbing Code (CPC) §703.0 (Table 703.1)Practice all 360 questions free — no signup required.
Related questions on this topic
- A 4 inch building drain sloped at 1/4 inch per foot is permitted a maximum load of how many drainage fixture units (DFU)?
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