Customer had a sewer smell coming from the kitchen sink. I let him know that it could be from recently moving in and no water being ran through and I also recommended to treat the line with the enzyme to help odor smells and fight grease., customer ended up buying our treatment and we treated the line before leaving, and I let them know if the odor smell is continue to happen after running in the water and in the line, the next step will be replacing the Studor vent ,