Are air admittance valves to code?

Author: Darrel Hessel  |  Last update: Saturday, January 31, 2026

Individual and branch-type air admittance valves shall conform to ASSE 1051. Stack-type air admittance valves shall conform to ASSE 1050. The valves shall be installed in accordance with the requirements of this section and the manufacturer's instructions.

What are the rules for air admittance valves?

AAVs shall be accessible, should replacement be required. Such valves shall be installed in a location that allows air to enter the valve. The AAV shall be installed not less than 6 inches (152 mm) above insulation materials that may block air inlets or otherwise impair the operation of the device.

In what states are air admittance valves legal?

They are not illegal in California as a state because California Plumbing Code allows "Engineered Vent Systems" see Section 911.0.

What is the downside to an air admittance valve?

The main problem with using an Air Admittance Valve instead of a Soil Vent Pipe, as discussed earlier, is that by preventing the gases from escaping through the top of the soil stack you are causing them to be forced down into the main drains and sewer system instead.

Are cheater vents legal?

Sometimes called "cheaters," these tubular, spring-loaded $5 vents are rated for only 1/2 DFU (drainage fixture unit), and are not allowed under most building codes.

Air admittance valves for plumbing venting explained, [just over 4 minutes]

Why is Studor vent illegal?

The Studor vent lets that air to be sucked in the pipe during water flow but doesn't let sewer gas escape out. Code is the thing that determines pipe size and also water flow. Hence no studor vents are permitted to toilets because more air is required to keep water flow going with more waste added to the toilet.

What is the life expectancy of an air admittance valve?

Air admittance valves have a typical life expectancy of 20-30 years, so if you start to have issues with sewer gases or smells being released around your sink or in the attic-wherever installed- the air admittance valve could be faulty or failed and should be replaced as soon as possible.

Are air admittance valves code compliant?

Vent systems using air admittance valves shall comply with this section. Individual and branch-type air admittance valves shall conform to ASSE 1051. Stack-type air admittance valves shall conform to ASSE 1050.

How long does an AAV last?

How long does an AAV last? Adeno-associated viruses (AAVs) are stable for several months to years when stored properly at -80°C.

Does an air admittance valve stop smells?

Air admittance valves often feature rubber seals, to help create a complete seal, increasing the effectiveness of the valve and preventing any odours from escaping through small gaps.

What is the difference between an air admittance valve and a cheater vent?

Automatic air vents are spring type devices often referred to as in-line or cheater vents, while air admittance valves have no spring. Air admittance valves are more expensive and are approved in many jurisdictions where in-line and cheater vents are not because of their moving parts (springs).

Does the AAV go before or after the trap?

Air admittance valves are typically placed between the P-trap of a fixture and the drain line. They're usually mounted on one leg of a sanitary tee, with the other leg going to the drain. The unit must be placed per local codes and the manufacturer's instructions.

Where is the best place to put an air admittance valve?

AAV location

An AAV should be located within the maximum developed length permitted for the vent. It must be located a minimum of 4” above the horizontal branch drain, 6” above any insulation material and within 15 degrees of vertical.

Can you vent a bathroom group with an air admittance valve?

AAVs are a great alternative if you can't connect to an existing venting system due to complex pipe routing issues or obstructions – an ideal venting solution for island sinks, remote bathroom groups, home remodels and additions that would otherwise have to be tied into a stack vent utilizing specialized venting ...

What is the minimum height for AAV?

The stack-type AAV shall be located not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented. The AAV shall be located within the maximum developed length permitted for the vent.

Will an air admittance valve help a slow drain?

These valves not only save space but also help keep sewer gas out of your home, promoting cleaner air. If you notice slow drains or gurgling sounds from sinks, it might mean there's negative air pressure in your drainage system, and that's the ideal time for these valves to be beneficial.

What are the disadvantages of AAV?

Limitations include the occurrence of immune-mediated toxicities, the potential loss of correction in the long run, and the development of neutralizing antibodies against AAV vectors preventing re-administration.

How to tell if an air admittance valve is bad?

Another way is field testing in a cup of water, Place the air admittance valve (AAV) in a cup as shown below. This creates a positive pressure which seals the membrane and allows the valve to float. If the AAV sinks then most likely the membrane has been compromised which allows air to pass through the AAV and sink.

Does a toilet need an AAV?

Yes, an air admittance valve can be used to vent a toilet. This valve is a device designed to allow air to enter the plumbing drainage system to balance the pressure, keeping water from getting pulled out from traps in the plumbing fixtures.

Do air admittance valves stop working?

Providing it is fitted correctly, there is little that can go wrong with an air admittance valve and this will be largely due to the valve malfunctioning or failing over time.

How high should an air admittance valve be above a toilet?

How high should you install the air admittance valve? The short answer is a minimum of 200mm above any water entry point. So if you imagine your soil pipe run, then durgo valve / AAV must be fitted above the highest connection to the soil pipe from any sink, bath or toilet that is connected to it.

Are air admittance valves a good idea?

An AAV can significantly reduce the number of venting materials needed in a plumbing system. That's money in the pocket of the plumber. They also allow greater flexibility in the layout of plumbing fixtures and reduce long-term roof maintenance. If we don't have a hole in the roof, it's easier to maintain it.

Where are air admittance valves not allowed?

Air admittance valves are not permitted in spaces where pressure conditions adversely affect the valve's operation. They are also not allowed in concealed wall and ceiling spaces used as plenums as part of an air distribution system that is under negative or positive pressure.

How high should air admittance valve be under sink?

Individual and branch-type AAVs shall not be located not less than 4 inches (102 mm) above the horizontal branch drain or fixture drain being vented.

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