12/12/2025
Why would you need an Air Admittance Valve?
AAVs (also called "cheater valves" and "mini valves") provide an alternative if you can’t connect to an existing venting system due to complex pipe routing issues or obstructions. It is an ideal venting solution for island sinks, remote bathrooms, home remodels, and additions that would otherwise have to be tied into a stack vent. AAVs allow homeowners more flexibility in the layout of their plumbing fixtures.
The air admittance valve (AAV) allows air into the plumbing system, which prevents a vacuum from forming when water drains and stops it from siphoning the water out of a P-trap. This prevents smelly sewer gases from entering your home and ensures that fixtures like sinks and toilets drain properly.
AAVs offer various benefits for do-it-yourselfers, particularly when it is not possible to connect to an existing venting system or when aiming to avoid roof work. For DIY'ers, AAVs eliminate the need for making roof penetrations, which can be complicated and require professional help. When installed correctly, they’re a great way to save time, money, and frustration.
Check out our blog where guest writer Sean Comerford shares instructions, tips, and video on installing an AAV!
