UPC Section 906 controls where a plumbing vent pipe can end so sewer gas leaves safely and cannot re-enter the building. A vent through the roof must rise a set height above the roof and stay a set distance from any door, window, or air intake.
The Uniform Plumbing Code is published and copyrighted by IAPMO. This page explains the section in our own words with a short excerpt only. Read the full official text at the source.
A plumbing vent lets sewer gas escape and lets air into the drain system so traps hold their seal. But where that vent pipe ends matters as much as the fact that it exists. If a vent dumped sewer gas right next to a bedroom window, it would push the smell back into the house. UPC Section 906 sets the rules for where a vent can terminate so the gas leaves safely and stays out.
What this section says
The code controls two things: how high the vent rises above the roof, and how far it stays from openings into the building. The height rule is stated directly:
Each vent pipe or stack shall extend through its flashing and shall terminate vertically not less than 6 inches (152 mm) above the roof.
That minimum keeps the opening above the roof surface and above any water or snow that could block it. The code raises the requirement where a roof is used for anything besides weather, such as a deck, so the vent ends well above head height there. The second rule is about clearance from openings. A vent has to terminate a set distance away from any door, openable window, or air intake, and it must not end under an overhang or soffit where gas could collect. The intent is simple: sewer gas leaving the vent should disperse into open air, never drift back through a window or get pulled into a fresh-air intake.
When this comes into play
This section governs every vent that penetrates a roof, which is most of them. Picture a bathroom addition whose vent has to tie through the roof near an existing upstairs window. Section 906 decides whether that penetration point is legal, based on how far it sits from the window and how high it rises. A vent placed too close to an opening, or cut off too short above the roofline, will fail inspection and can cause real odor complaints inside the home.
What this means for you
If part of your house smells faintly of sewer gas near a window, especially on a still day or when rooftop wind pushes down, a poorly located or too-short vent terminal can be the cause. That is a code-layout issue, not a clog. For the full set of vent termination distances and heights, see plumbing vent termination rules. For how a vent must be graded and tied in before it reaches the roof, see UPC 905 vent grade and connections. Where there is no practical path to the roof, an air admittance valve is sometimes allowed instead. Because moving a roof penetration means roofing and flashing work, this is best confirmed and placed correctly at the time the vent is run.
Full text and source
UPC Section 906 is part of the Uniform Plumbing Code. IAPMO publishes and holds the copyright on it. The excerpt above reflects the rule as adopted; Phoenix enforces the 2024 UPC with local amendments, so verify the current heights, distances, and section numbers. Read the vent-terminal rules on UpCodes, or confirm local amendments through the City of Phoenix: phoenix.gov/pdd.
Keep Reading
- UPC Table 1002.2: Maximum Trap Arm Length by Pipe Size
- UPC 1003: Which Fixture Traps Are Allowed (and Banned)
- UPC 1007: Trap Seal Protection for Floor Drains
- UPC Section 1101: Storm Drainage and Roof Runoff
- How high does a plumbing vent have to be above the roof?
- What is a plumbing vent and why do vent pipes matter?