True or False: Under the UPC, storm water from a roof may be discharged into the building's sanitary drainage piping, provided that piping is sized to carry the extra flow.
Not quite. The answer is A: True
Storm water must not be drained into piping or sewers intended for sanitary drainage, no matter how much extra capacity the sanitary pipe has. Roofs, paved areas and similar surfaces go to a separate storm drainage system, a combined sewer only where no separate storm sewer is available, or another approved point of disposal — and what a downstream municipality does with its own system is its decision, not a license to combine the two inside a private building.
Reference: UPC 2021 §1101.3; §1101.2 (Storm water drainage to sanitary sewer prohibited)
Checked against the official text
Checked against the 2021 UPC text. Washington's exam is written against the 2015 edition, which we have not read for this section, so confirm it against your 2015 book.