Customer called back for us to redo the plumbing for the downstairs sink/laundry. Upon arrival found that laundry line from first floor and downstairs sink are tied in together and causing line to get overloaded when laundry is running. Went ahead and cut out pipes underneath sink. Separated sink and laundry lines. Upsize laundry line to 2”. Went ahead and augured drain line as well. Ran plenty of water from sink and washer. Drain line no longer backing up. Need to come back on Jan 2 morning to install a one way check valve for basement sink in the case of the event if the drain line backs up, it won’t cause the basement to sink to overflow. This will part of the paid invoice. No warranty on drain auguring. 1 year warranty on pipe repairs.