I just bought my place a few months ago but just moved in recently. I live in the bottom level of a 3-level condo complex.

I've found that my guest toilet has the tendency to acquire bad smells and cloudy water while I'm away at work (I've never been in the bathroom when it's changed states so I can't speak to the mechanism). The toilet appears to flush fine, and I hardly use it, so I don't think it's because I forget to flush (although I could blame the occasional guest). It doesn't flood.

I can't relate it to times *I* use the plumbing system (baths, etc.). It doesn't do it every day, but it's happened often enough that I'd like to try and get it fixed. Is it backing up? Is it just a lousy toilet put in years ago that doesn't fully flush? Any ideas or help is appreciated.

(Thanks for taking the time to read this).