Plumbing Vent Traps

Author: Pacific Northwest Inspections Group, LLC   Date: 25-Nov-2013.   Category: Plumbing   Add to Favorites 


A trap - the bend in the drain below every plumbing fixture - creates a water seal that blocks sewer gases from escaping into the house. A vent prevents the trap water from siphoning away. Vents maintain equal air pressure on both sides of the trap seal. This keeps negative pressure from building up so that a slug of water running down the drain doesn’t pull the trap water out with it.