TL;DR
An air admittance valve is a one-way mechanical vent that opens under the slight vacuum of draining water to let air into a plumbing drain, then springs shut so sewer gas cannot escape into the room. It substitutes for a vent pipe through the roof where running one is impractical, classically under island sinks and in basement or accessory-unit bathrooms.
What it means
An air admittance valve is a one-way mechanical vent that opens under the slight vacuum of draining water to let air into a plumbing drain, then springs shut so sewer gas cannot escape into the room. It substitutes for a vent pipe through the roof where running one is impractical, classically under island sinks and in basement or accessory-unit bathrooms. Codes accept devices meeting ASSE 1051, though some jurisdictions restrict where they may replace open venting, and they must remain accessible for replacement. A gurgling drain or sewer smell at the cabinet usually means the seal has failed.
Where it sits in the glossary
Air admittance valve is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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