James White, 64, had gone missing from the home in Owings Mills on Feb. 26, and his body was found in the pool in the 8100 block of McDonogh Road on April 28, police said.
White was pronounced dead at the scene.
At the time of his disappearance, police had described White as being non-verbal and intellectually disabled.
"He does not understand that he has to pay for things when he goes into a store and may get accused of shoplifting," police said.
White's death has been ruled an accident, with the cause listed as drowning complicated by hypothermia, police said. No foul play is suspected and no criminal charges will be filed, police said.