Hello, My problem is that my washer drain overflows during drain down of washer water. It appears to be a 1 1/2" line and is shared with dishwasher and kitchen sink. There is a crawl space under laundry room and trap is located below floor in crawl space area. My drainage system feeds into a septic system although My toilets flush fine and there is no back-up apparent in tubs. I can hear a gurgle sound in kitchen sink during washer drain-down. Do you have any ideas?
John