23-year-old Sean Hughes and 25-year-old Heather Rivas were arrested on Wednesday.
Firefighters attempted to save Victoria Rivas' life, but she was eventually pronounced dead at a hospital.
Investigators say Hughes was responsible for taking care of the little girl while her mother was taking a nap.
We're told there was a functioning lock on the pool gate, but it was propped open, and the doggy door leading to the pool area was unlocked.
According to officials, drug paraphernalia indicating possible drug use was found inside the home.
Hughes faces 2nd degree murder and child abuse charges; Rivas faces child abuse charges.