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Is It Possible To Use An Air Admittance Valve For Venting A Toilet?

Can an Air Admittance Valve be Used to Vent a Toilet?

Venting a toilet is an essential aspect of plumbing design to ensure proper drainage and prevent problems such as slow flushing, gurgling sounds, or the escape of sewer gasses. The venting system in a plumbing setup is responsible for allowing air to enter the pipes, maintaining the right pressure, and facilitating the flow of wastewater.

Proper venting is crucial for the effective and trouble-free operation of toilets and other plumbing fixtures in a building. Is an air admittance valve a practical option for toilet venting? Let’s explore this further by delving into the considerations and factors associated with the use of this valve in toilet venting.

What Is an Air Admittance Valve?

An air admittance valve, commonly known as a cheater vent, is a mechanical device used in plumbing systems to vent sewer gasses and allow air to enter the drainage system. It is designed to replace traditional vent pipes that typically go through the roof of a building to allow air to enter the plumbing system and prevent the creation of a vacuum, which could draw water out of traps in plumbing fixtures.

Can You Use an Air Admittance Valve to Vent a Toilet?

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. It serves as an alternative to traditional venting methods that use pipes that extend through the roof. 

When using this valve to vent a toilet, it is essential to follow local plumbing codes and regulations. Some jurisdictions may have particular requirements regarding the use of these valves, and not all areas allow them in all situations.

Other Ways to Vent a Toilet

Apart from using an air admittance valve, there are several traditional methods for venting a toilet, and the choice often depends on the specific plumbing layout and local building codes. Here are some common ways to vent a toilet:

  • Individual Vent Pipe

In this method, each plumbing fixture, including toilets, has its own dedicated vent pipe. This vertical pipe extends through the roof and permits air to enter the plumbing system, preventing the drawing of water out from traps. Individual venting is a common and straightforward approach, ensuring each fixture has proper ventilation.

  • Common Vent Stack

Multiple fixtures on the same floor can share a common vent stack. The vent stack, a vertical pipe reaching through the roof, functions as a shared vent for multiple fixtures, including toilets. This method is often used to simplify plumbing installations and reduce the number of pipes penetrating the roof.

  • Venting Through an Existing Stack

If the toilet is located near an existing vent stack, it may be practical to tie into that stack to vent the toilet. This approach minimizes the need for additional vent pipes and can be a cost-effective solution. Proper sizing and connection methods are crucial to maintaining adequate venting.

  • Wet Venting

Wet venting involves using a single pipe for both draining and venting purposes. This method is more complex and requires careful design to ensure proper drainage and ventilation. It is often employed when multiple fixtures are in close proximity. The wet vent must be appropriately sized to accommodate the drainage needs of all connected fixtures.

  • Horizontal Wet Venting

Similar to standard wet venting, horizontal wet venting uses a horizontal pipe to serve as both a drain and a vent. This method is useful when designing plumbing systems in confined spaces where vertical vent pipes are challenging to install. Careful consideration of pipe sizing and slope is necessary to maintain effective venting and drainage.

Air Admittance Valve FAQs

How do I know if my air admittance valve is working?

You can conduct a simple visual inspection to determine if your air admittance valve is functioning correctly. Check for any visible signs of damage, deterioration, or debris around the valve. Additionally, some models may have indicators, such as a ball or diaphragm, that move when the valve is actively allowing air into the plumbing system. 

If your plumbing fixtures are experiencing drainage problems or unusual gurgling sounds, it could indicate a malfunctioning valve and professional inspection or replacement may be necessary.

Where are air admittance valves not allowed?

The use of these valves is subject to local plumbing codes and regulations. While they are accepted in many areas, some jurisdictions may have restrictions on their use, particularly in certain applications. In some regions, these valves may not be allowed for venting systems serving multi-story buildings, high-rise structures, or critical installations. It’s crucial to consult local plumbing codes and authorities to determine where these valves are permitted and under what conditions.

What happens if an air admittance valve fails?

If an air admittance valve fails, it can lead to negative pressure issues within the plumbing system. This could lead to the suction of water from traps in plumbing fixtures, causing unpleasant odors, slow drainage, or even backup issues. In some cases, a failed valve might allow sewer gasses to escape into the living space, posing health and safety concerns. 

Can an air admittance valve be installed outside?

Yes, but these valves are designed for indoor use and not intended for outside installation. These valves are typically placed in accessible locations within a building’s plumbing system, serving to allow air into the drainage system to prevent siphoning of water from traps in plumbing fixtures. Exposing an air admittance valve to outdoor conditions, such as rain, extreme temperatures, and other environmental elements, may compromise its effectiveness and durability.


Having a well-vented toilet is vital for a smooth plumbing system and avoiding issues like slow flushing or bad smells. Air admittance valves are a practical option for venting toilets, but it’s crucial to follow local rules. Different places have different requirements, so it’s important to stick to the plumbing codes in your area to keep things safe and up to standard.

If you’re considering air admittance valves for venting your toilet, consider our services for a hassle-free and reliable plumbing experience. At Rustic Yard Events, we not only understand the importance of proper venting for your plumbing system but also prioritize compliance with local codes to ensure your safety and satisfaction. Book an appointment today.

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