What is a common RV odor Issue? Well, it’s not what you might think.

There are many things that can cause odor issues in a Travel Trailer. Most of the time odors revolve around improper grey or black tank maintenance. However there is another common problem that occurs more frequently than you might think; a bad air admittance valve.

You probably have more than one air admittance valve in your RV. They are typically located under the sinks. So what does an air admittance valve do? Well it allows air into your plumbing system so that the tanks can drain properly when there is negative pressure. Secondarily, after it allows air into the plumbing system it also prevents gases from coming back into the inside of your travel trailer. It also keeps the water from siphoning out of your plumbing p-traps. If those p-traps are empty, grey tank gasses are going to come right into your rig.

The Air Admittance Valve

While you might jump to the conclusion that a bad odor must be coming from the black tank, guess again. Grey tank odors that come from a bad air admittance valve are every bit as nasty as black tank odor…sometimes even worse. This is because the grey tanks collect dirty dishwater that houses bacteria, body oils, perfumes, and soap (which contains odor producing fats) etc. When this dirty grey water sits in the holding tank it gets nasty fast.

I would like to tell you that the air admittance valve will never fail, but that would be a lie. As a matter of fact we have had a failure twice. Once on our Jayco when it was less than a year old, and now on our 2017 Grand Design.

The valves that come from the factory on the Grand Design are glued on. Needless to say that did not make me happy as the old valve needed to be cut off. Once I cut the old valve off, I had to glue the new valve on. The whole procedure was probably a twenty minute project.

I did not replace the valve with the same one the factory installed because I feel they are very cheap. I upgraded to a Studor Air Admittance Valve. It is a higher quality valve and now should it ever fail I can unscrew it and just screw a new one on. It comes with either a PVC or ABS adapter that accepts 2″ and 1 1/2″ pipe. I made the mistake of getting the PVC fitting instead of the ABS (my drain pipe is ABS). So I ended up having to buy glue for fitting ABS to PVC Pipe. This wasn’t the end of the world but just learn from my mistake!

Studor Air Admittance Valve Installed

As with everything, if you are not comfortable doing this kind of work, let a professional do it for you. There are some things you will want to keep in mind when you are gluing ABS joints together:

  1. The purple primer will stain your floor is you spill it. Someone at the RV dealership did this to our Coachmen Travel Trailer and they ended up replacing the bathroom flooring.
  2. Once the Glue is applied you have very little time to put the pieces together so get everything ready to assemble before the glue stage.
  3. Because of 2 above, I would recommend you dry fit everything before you even start.
  4. Tons of how to videos exist on YouTube that will show you how to do this job.

Hopefully you will never have this problem, but if you smell a funny odor it may just be this valve.