1995 Legend Sedan - Water Leak?

My beloved Legend hit 205,000...still breaking her in after 18 years of ownership. Started overheating last March so replaced radiator and thermostat. Seemed to work for the most part but overheating did still happen. Finally determined it was head gasket after tinkering with cooling system and thermostat sevreral times. Could still not part with this car so sunk in the cash to get her fixed up. Now with new head gasket, radiator, thermostat, tires and breaks she is practically new.
Did notice a strange leak which appears to be water coming from under the chassis behind the rear passenger wheel in the quarter panel. Cannot imagine how water can be trapped in this area. The leak is emminating from one particular bolt. It just slowly drips. I keep the car garaged so I can see a small puddle form over time in the garage. The leaking has subsided but curious as to possible causes. The only other clue is the carpeting on the right side of the interior trunk was wet which drained into the storage well. Not sure if my mechanic spilled something while keeping my car for 5 days fixing head gasket. Any thoughts welcome. Tried to include picture but file size too big. Thanks