In plumbing, why is proper venting important?

• A. Improve water pressure
• B. Prevent sewer gas buildup and ensure trap seals
• C. Increase water usage
• D. None of the above

Answer: (B)

Venting in plumbing serves to balance air pressure in the drainage system as water and waste flow through the pipes. When a fixture drains, it can create a vacuum that pulls the water out of nearby traps. The water in traps is what blocks sewer gases from entering the living spaces. If the trap water is siphoned away, gases can escape into the house and drains may gurgle or drain slowly.

A proper vent path gives air a place to enter the system and lets sewer gases escape safely above the roof. This keeps the trap seals intact and prevents the buildup of odors inside the home, while also helping the drainage flow smoothly.

That’s why the best choice highlights preventing sewer gas buildup and ensuring trap seals. The other options don’t address the real purpose of venting—venting doesn’t directly improve water pressure or increase water usage.