Backed up kitchen drain overflows
I live in the basement suite of a four story walk up apartment building. My kitchen sink is forever bubbling up with water or soap suds from other apartments. With this there is black/brown residue that is brought up with it. Two days ago, my sink backed up again, but this time it overflowed and flooded my entire kitchen, spilling over and drenching my living room carpet. My main question is: what is in that water as my apartment now stinks? A few people have told me that is it sewage water etc. Is that possible?