Bad Smell In my Limo Help!

For some time now my Limo has been smelling like a mens bathroom. I keep tring differant things but it keeps coming back. It has new carpits and has had some water damage but was cleaned up. It seems that the smell goes away if i dont drive it for a month. But comes right back. Help. Its very bad. Thank you. (fyi, its not from cleints parting in the back)

Was the cabin filter replaced?
The smell might be coming from the air duct work.