Per the UPC drainage fixture-unit table, what is the DFU rating of a water closet using 1.6 gallons per flush or less, flush tank type, in a private residence?
Not quite. The answer is B: 3
Table 702.1 rates a private-use 1.6 gpf gravity-tank water closet at 3 DFU; the same closet in public use is 4 DFU and in assembly use 6 DFU, and a closet using more than 1.6 gpf rates 4 DFU even in private use. The usual error is pulling the public or assembly column when the stem says private residence.
Reference: UPC 2021 Table 702.1 (Drainage Fixture Unit Values)
Checked against the official text
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