Core TradesQuestion 139 of 700
The primary purpose of a vent in a drain-waste-vent (DWV) system is to:
a.Increase the water pressure at fixtures
b.Protect trap seals by preventing pressure differentials in the drainage system
c.Speed drainage by adding water to the pipe
d.Filter sewer gas before it reaches the roof
Explanation
Vents admit air so that draining water does not create suction or back-pressure that would siphon or blow out trap seals. They equalize pressure, keeping seals intact. Vents do not boost supply pressure, add water, or filter gas; they carry gas safely above the roof.
Law Reference: 2025 CA Plumbing Code §901.0Practice all 700 questions free — no signup required.
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