Why does the smelly drain water from disposal and washer :confused: come up in basement shower

why does the smelly drain water from disposal and washer :confused: come up in basement shower

You have a partial clog in the drain line downstream from the floor drain. Go down the kitchen vent on the roof or the nearest roof vent from the floor drain and snake it out. Put out enough cable to reach the base of the vent and about 20' more. Afterwards test and then flush out the line with a garden hose. Good luck, Tom