Sulfur smell from shower drain
My wife and I have gone through a long and painful process redoing a downstairs bathroom. We are quite close to being completed...
However, now we seem to have a fairly strong smell of sulfur in the bathroom - appearing to be coming up from the shower drain. This particular bathroom has not been used in ~ 8+ months, but the smell has just become noticeable within the last 5 days. We have tried pouring water and some bleach down the drain w/ limited success - with the smell returning. If the upstairs toilet is flushed, it seems that the smell in the downstairs bathroom gets stronger...
Could this be due to bacteria that had been present in the drain pipe that hadn't seen water for a while, but now has some water in it?
Is there a way to properly assess this and fix it?
It would be a shame due to the marathon of work and $$$ involved to rip anything apart again.
Help!