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!

Is there a trap in the 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!
I believe that there is a trap in the drain - we did nothing to change any of the pipe proper.

The smell also does not appear to be coming from the pipe for the sink, nor from the pipe from the toilet (neither have been put in place yet).

Could this be a vent issue?

No toilet installed? No sink installed?

How are these drain lines sealed?

The smell could easily be eminating from them. Sometimes it is hard to determine the exact source, but in an enclosed space, they will accumulate.