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.
verb (used without object), subsided, subsiding. 1. to sink to a low or lower level. 2. to become quiet, less active, or less violent; abate: The laughter subsided. 3. to sink or fall to the bottom; settle; precipitate: to cause coffee grounds to subside. Origin of subside.