Some people only have the problem when they run water in a sink or a bathtub. The source of the odor in almost all of these instances is a buildup of biofilm on the sides of the pipes that connect the sink or fixture to the actual P-shaped trap under the fixture.
Subsided is defined as  calmed down or sunk to a lower level. When the noise of a crowd dies down, this is an example of when the noisesubsided.
The adjective subdued refers to something, like a sound, that has a lowered intensity. Your loud conversation with a friend in the back of the classroom is likely to become subdued when the teacher passes out the exams. Something that is subdued has lost some of its strength or intensity.