Customer had been smelling sewer smell by washing machine in laundry room. When going into laundry room did not smell anything but laundry detergent. When filling up washing machine and draining it I then smelt the sewer smell. Informed customer I would need to run sewer machine down line to clean out build up and the. Run the system through a full cycle with laundry soap and hot water to clean out drain line. Customer approved estimate. Ran hand held machine down system and pulled back hair and a dryer sheet. System is running now with hot water and laundry detergent.