We recently had a refrigerator with an ice maker installed. One bathroom is just behind the kitchen wall.
The folks that installed it ran a tube from the bathroom under sink cabinet, drilled a hole in the wall, and ran the tube to the refrigerator.
Ever since then, we've had an odor coming from under the sink. Not all the time, but when it's there, it's pretty pungent. It smells almost like septic (we're on a septic tank), but not as bad.
I've used expanding foam to cover any gaps between pipes and the wall, but the smell continues. We get it no where else in the house. The shower and the sink are used regularly, so there is water in the traps.
john in sumner wa
hello..well unless he drilled through top of drain pipe or vent,,,i would check your sink overflow..the little hole in front of your sink...we have flushed out hundreds,,,and the smell is terrible..check out ezplunger.com..this tool cleans out the black scum..good luck