OK, first off, I know nothing about plumbing. That said, The other day, the apartment smelled, for lack of a better term, like a stale fart. I went to all of the sinks, toilets, bathtubs to see if the odor was strong around any of them. No such luck. The smell just seemed to linger in the general area. It's had that same stale ass smell for a week. Anyone have a clue as to why?
One too many popeye's dinner bowls? I kinda doubt you'll get any serious replies. This thread could be comedy gold. hard to say without some sort of location of origin.
When this similar sort of thing happened at my house about 4 years back, it turned out we had to replace the main line that ran to the tie-in with the city....an expensive fix.
roots break through the line eventuallly and clog everything up...plus, the settling of the ground over time pushes parts of the pipe so gravity starts working against you instead of for you. essentially, the crap gets stuck back. you'll know it's the problem for real when your toilet kinda bubbles up when you flush it..makes a "glub" type noise. they'll snake a camera down in the line and show you...you can see the roots that find their way in. my house is about 40 years old....they replaced the line with super duper PVC, so even if I die in that house, i shouldn't have to worry about replacing this thing again.
Are there any sinks or showers that you don't use often? Perhaps the U joint dried out and its allowing gas back up the line. Run the water in all the sinks and showers for a couple minutes to see if that can fix it. If not, you may need a plumber.
Have all the toilets and sicnks been flushed/had water in them? I could be a dried out p trap if you have not used one of them in a while.
I had a similiar problem although I know you checked all the toilets....the back toilet in the guest room was starting to smell even after my wife clean the bathroom. We coudn't figure out where the smell was coming from for a while; turns out, it was from the toilet water. So what we did was buy a couple of chlorine tablets and put them in the flusher portion of the of the toilet. The complex woudn't fix it, they said the smelly water was due to the pipes and thats the city of houston's problem....so there you go.