I have a recurring sewer odor that seems to be coming from the bath tub and shower in my two bathrooms.

Usually in the morning the odor is noticeable when I start to shower.

My wife has also complained about the smell in the other bathroom occasionally where we have a bathtub installed.

Tonight without running shower or bathtub the odor was even noticeable part way into the living room.

I live in a condo unit with three floors. My unit is on the second floor.

I was thinking the only way that this could happen would be if there were no trap installed in the drain line.

Any thoughts on other possibilities would be appreciated.

How could I be sure if a trap is installed on a shower or bathtub without doing demolition?

Thank you.

On the shower, remove the cover, put a thin layer of toilet paper over the drain, go flush the toilet, watch the paper. On the tub, remove the overflow cover, run a coathanger down till it hits bottom with toilet paper taped to the last 6 inches of the wire, it is is not completely wet it has no trap.