Deputies went to the area early Wednesday morning after a report of a vehicle in the water with a man calling for help.
When deputies arrived, they found the man sitting in the water talking to himself. Wilson Emergency Management Agency officials assisted in getting the man out of the water.
During the rescue, dispatch gave another call about a possible house fire on Wrencrest Drive.
Deputies arrived to find a detached garage with an upstairs apartment fully engulfed in flames.
Deputies said the homeowner was also the subject recovered from the lake.
The 77-year-old man suffers from mental disorders and told deputies he set the garage on fire, panicked and left in his vehicle.