We had our bathroom remodeled about 9 months ago. Since then, and never before then, our bathroom stinks. It has two distinct smells. One that comes and goes (but is mostly around) smells like rotting animal, or like a wet rotting hay. It seems like it could be coming from the water closet, or just outside of it. The other smell, which also comes and goes, is a sewer like smell. Only the toilet area smells like this. At times it smells like pure methane, which just gags us. We have a septic system. No other drain in this bathroom,nor the second toilet just on the other side of the wall in another room have this smell. I can't stand it anymore! Our house is one level, and sits on a concrete foundation. The flooring in the bathroom is tile. Could these smells be related, or is it a crummy coincidence they hit at the same time and place? All I do know is that it never smelled prior to the remodel. Could it be mold? A dead critter? How do I find out? Call a plumber for the sewer smell? I can't call the contractor, he doesn't do quality work. Suggestions?

As you clearly stated. Your contractor doesn't do quality work. I would call in a License Plumber to perform an onsite evaluation, to determine if the original work was done properly and what is lacking.

Best Wishes

I'd bet that the sewer odor is coming from the wax seal area under the toilet. They probably left the toilet flange as is , tiled around it and reset the toilet. The flange should have ben removed and replaced after the tile was finished, or at the very least a flange extender added atop the old flange.