The drowning happened along the 2800 block of Winchester Avenue shortly before 11:30 p.m.
The man was an invited guest of the homeowner, Philadelphia Police Lt. Aisha Perry.
It appears alcohol may have played a factor in the death. Police tell Action News that the man apparently fell in the pool - a pool described by sources as being as "green as a swamp" and that you could not see the bottom.
Foul play is not suspected as it appears to have been an accident.
Northeast detectives are handling the investigation.