Found improperly sized line set, causing sweating on the indoor unit and symptoms of a restriction. Found no water in emergency drain pan and water flowing normally through primary drain line. Extensively tested drainage on both drain lines and found no issues. Tenants pointed me toward a copper line near the front door that was dripping water. From the attic I could only see copper lines going from the hot water heater to the side of the house with front door. Both drain lines for the ac unit ran to the other side of the house and were pvc all the way. The emergency drain line drained on the back porch and primary appears to be tied to the neighboring apartment. Found return duct crushed by hanging strap. Cut the strap to allow more airflow to unit. Measured 27 degree temperature split from supply to return probably caused by restriction from undersized line set. Unit operating normally upon departure. Customer stated he would pay tomorrow once they had the card.