A house member had some health issues the past few months and, for a while, another house member was pouring buckets of urine down the shower. It developed something of a smell which we tried to extirpate with bleach and vinegar.
However, there's still a lingering odor, and, through the grating, I can see what looks like a loose seal of some sort.
Pulling off the grate, it looks like this:
I'm worried that some kind of seal is broken and is either (a) letting gases up from the sewer or (b) the smells of waste that snuck into the cavity below the shower.
Any thoughts on what may have happened and how to fix this?