If you do not use the tub and no water is run into the drain periodically, then odors are coming out of it. Where you smell the odor is not necessarily where it is occurring. You will smell the odor a places where they can accumualate without excessive air movement. seal the tub drain and then see if the odor disappears.: We have a terrible sewer order in our two year old house. The smell is the worst during the hot summer days. It is unbearable right now. I cannot find a source for the smell. We do have an old footed tub that we do not use but the smell does not come from that area. It centers around our stairs and in my daughters bedroom. Is there something in the walls where the order can be coming from since it does not seem to be a sink or tub? Please help. Thanks in advance.