When we leave the house we turn the gas hot water heater down to the lowest setting, and the thermostat down to 55 degrees. When we return we find a puddle of water, 12 ounces under the sink. Its does not occur at any time except when adjusting settings on the furnace and water heater and leaving the house. When we come home the pan which we place under the sink has water in it but the surrounding pipes and the under side of the sink is completely dry. My first thought is some kind of condensation, BUT 12 ounces???? It never leaks when we are at home. NEVER
See attachement for view of sink set up.