Natalia Harding, a 21-year-old resident of Bear, was charged with a felony count of endangering the welfare of a child.
The incident happened on Thursday, April 18 at Gordy's Little Angels Day Care on the 300 block of Hackberry Drive.
According to police, the owner of the day care had gone to the store and left Harding in charge.
Detectives determined she was inside making lunch while a group of unsupervised children played outside.
At some point, police say Harding noticed the 3-year-old was in the water that had collected on top of the cover of the above-ground pool.
Harding removed the child from the water and called 911. The child, who was also suffering from hypothermia, was treated and released from Nemours Children's Hospital.
The day care was temporarily shut down the next day, and an arrest warrant was issued for Harding on Monday. She turned herself in on Tuesday.