A 2-inch horizontal sanitary branch must be installed at 1/4 inch fall per foot. What total fall is needed over a 24-foot run?
Correct Answer
A) 6 inches.
At 1/4 inch per foot, a 24-foot run needs 6 inches of total fall.
Why This Is the Correct Answer
At 1/4 inch per foot, a 24-foot run needs 6 inches of total fall.
Why the Other Options Are Wrong
Option B: 3 inches.
3 inches. is below the supported result for plumbing drainage slope; it likely omits allowance, conversion, coverage, or final round-up.
Option C: 8 inches.
8 inches. is above the supported result for plumbing drainage slope; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Option D: 12 inches.
12 inches. is above the supported result for plumbing drainage slope; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Memory Technique
Checking Bathroom takeoff: count the condition before counting the package.
Reference Hint
Study anchor (closed-book): memorize Plumbing drainage slope from 2025 California Plumbing Code, California Code of Regulations Title 24 / Title 24 California Plumbing Code horizontal drainage piping slope; know the rule or calculation trigger without relying on exam-room lookup.
More Class B Trade Questions
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