TL;DR
A P-trap is the U-shaped fitting below sinks, tubs, and showers that holds a few inches of water as a seal, blocking sewer gas from rising into the room while letting drainage pass. Plumbing codes require one at nearly every fixture, properly vented so siphoning cannot empty it; a dry one — common in unused floor drains and guest baths — is the usual source of a mystery sewer smell.
What it means
A P-trap is the U-shaped fitting below sinks, tubs, and showers that holds a few inches of water as a seal, blocking sewer gas from rising into the room while letting drainage pass. Plumbing codes require one at nearly every fixture, properly vented so siphoning cannot empty it; a dry one — common in unused floor drains and guest baths — is the usual source of a mystery sewer smell. Slip-joint versions under sinks come apart by hand for retrieving rings and clearing clogs.
Where it sits in the glossary
P-trap 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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