The name of the fifth person who died has not been released.
The 17-year-old's vehicle was found underwater after heavy rain in the area.
The Montgomery County Sheriff's Office said a group of teenagers was playing near a retention pond when a 15-year-old entered the water and did not resurface.
A five-year-old boy nearly drowned at a hotel pool, but in a stroke of fate, two off-duty firefighters were there and immediately got to work.
The family of a 2-year-old girl who nearly drowned during a Memorial Day gathering is fighting to keep her treatment options open as she remains hospitalized in critical condition.
Surfside Beach police are urging beachgoers to follow safety guidelines following the tragic drowning of an 11-year-old Joshua Lahai over Memorial Day weekend.