§ Chapter 31 IRC 2021
Vents
21 entries from Chapter 31 of IRC 2021, organized by section number. Each entry covers what the code requires, why it exists, what inspectors look for, and common mistakes.
§ 01 Sections
All 21 entries.
Sorted by section number. Click any row for the full entry — answer, requirements, edition diff, related sections.
Section
Title
Question
P3101.2
Every Trapped Fixture Needs Trap Seal Protection by Venting
P3101.2
Does every plumbing fixture need a vent?
Does every plumbing fixture need a vent?
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P3101.2.1
Every Trapped Fixture Needs a Protected Vent
P3101.2.1
Does every plumbing fixture need a vent under IRC 2021?
Does every plumbing fixture need a vent under IRC 2021?
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P3102.1
At Least One Plumbing Vent Must Terminate Outdoors
P3102.1
Does every house need a plumbing vent through the roof?
Does every house need a plumbing vent through the roof?
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P3102.1
At Least One Plumbing Vent Must Terminate Outdoors
P3102.1
Does a house need a plumbing vent through the roof?
Does a house need a plumbing vent through the roof?
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P3103.1
Roof Plumbing Vents Need the IRC Minimum Termination Height
P3103.1
How high does a plumbing vent have to be above the roof?
How high does a plumbing vent have to be above the roof?
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P3103.1
Roof Vent Terminations Need Required Height and Weather Protection
P3103.1
How high does a plumbing vent need to be above the roof?
How high does a plumbing vent need to be above the roof?
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P3103.5
Vent Terminals Must Stay Clear of Windows, Doors, and Air Intakes
P3103.5
How far does a plumbing vent need to be from a window or air intake?
How far does a plumbing vent need to be from a window or air intake?
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P3103.5
Plumbing Vents Must Be Kept Away From Openings and Air Intakes
P3103.5
How far must a plumbing vent be from a window or door?
How far must a plumbing vent be from a window or door?
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P3104.2
Vent Piping Must Drain Condensate Back to the Drainage System
P3104.2
Does plumbing vent pipe need slope?
Does plumbing vent pipe need slope?
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P3105.1
Trap Arms Must Reach the Vent Within the IRC Distance Limit
P3105.1
How far can a P-trap be from the vent under IRC 2021?
How far can a P-trap be from the vent under IRC 2021?
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P3105.1
Fixture Vents Must Connect Within the Allowed Trap Arm Distance
P3105.1
How far can a trap be from its vent?
How far can a trap be from its vent?
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P3106, P3107
Individual and Common Vents Serve Different IRC Layouts
P3106, P3107
What is the difference between an individual vent and a common vent?
What is the difference between an individual vent and a common vent?
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P3107.1
Two Fixtures Can Share a Common Vent Only in Specific Layouts
P3107.1
Can two sinks share one vent?
Can two sinks share one vent?
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P3108.1
Bathroom Groups Can Use IRC Wet Venting When the Layout Fits
P3108.1
Can a toilet, shower, tub, and lavatory share a wet vent?
Can a toilet, shower, tub, and lavatory share a wet vent?
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P3108.1
Bathroom Groups Can Use Horizontal Wet Venting Under IRC Limits
P3108.1
What is a horizontal wet vent in a bathroom?
What is a horizontal wet vent in a bathroom?
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P3109
Waste Stack Venting Is Limited to IRC-Approved Fixture Layouts
P3109
Can a drain stack also be the vent for fixtures?
Can a drain stack also be the vent for fixtures?
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P3112.1
Island Sinks Need a Special IRC Venting Method
P3112.1
How do you vent a kitchen island sink under IRC 2021?
How do you vent a kitchen island sink under IRC 2021?
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P3112.1
Island Fixture Vents Need a Code-Compliant Loop or Approved Alternative
P3112.1
What is the code way to vent an island sink?
What is the code way to vent an island sink?
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P3113.1
Vent Pipe Size Is Based on IRC Vent Sizing Rules, Not Guesswork
P3113.1
What size does a plumbing vent pipe need to be?
What size does a plumbing vent pipe need to be?
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P3114.1
Air Admittance Valves Are Allowed Only Under IRC Conditions
P3114.1
Are air admittance valves allowed by IRC 2021?
Are air admittance valves allowed by IRC 2021?
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P3114.1
Air Admittance Valves Are Allowed Only Where Approved and Accessible
P3114.1
Are air admittance valves allowed under IRC?
Are air admittance valves allowed under IRC?
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