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.
subside, lessen(verb) wear off or die down. The pain subsided. subside(verb) sink to a lower level or form a depression. the valleys subside. subside, settle(verb) sink down or precipitate. the mud subsides when the waters become calm. sink, subside(verb) descend into or as if into some soft substance or place.