Vents

Air Admittance Valves Are Allowed Only Under IRC Conditions

Are air admittance valves allowed by IRC 2021?

P3114.1

At Least One Plumbing Vent Must Terminate Outdoors

Does every house need a plumbing vent through the roof?

P3102.1

Bathroom Groups Can Use IRC Wet Venting When the Layout Fits

Can a toilet, shower, tub, and lavatory share a wet vent?

P3108.1

Every Trapped Fixture Needs a Protected Vent

Does every plumbing fixture need a vent under IRC 2021?

P3101.2.1

Individual and Common Vents Serve Different IRC Layouts

What is the difference between an individual vent and a common vent?

P3106, P3107

Island Sinks Need a Special IRC Venting Method

How do you vent a kitchen island sink under IRC 2021?

P3112.1

Roof Plumbing Vents Need the IRC Minimum Termination Height

How high does a plumbing vent have to be above the roof?

P3103.1

Trap Arms Must Reach the Vent Within the IRC Distance Limit

How far can a P-trap be from the vent under IRC 2021?

P3105.1

Vent Pipe Size Is Based on IRC Vent Sizing Rules, Not Guesswork

What size does a plumbing vent pipe need to be?

P3113.1

Vent Terminals Must Stay Clear of Windows, Doors, and Air Intakes

How far does a plumbing vent need to be from a window or air intake?

P3103.5

Waste Stack Venting Is Limited to IRC-Approved Fixture Layouts

Can a drain stack also be the vent for fixtures?

P3109