The incident occurred in Litchfield County around noon on Tuesday, Aug. 20, on Magnolia Lane in the Terryville section of Plymouth.
According to Edman Austin of the Plymouth Police, police, fire, and EMS found the child unresponsive in the pool and immediately began treatment.
The boy, whose age was not provided, was transported to Bristol Hospital for treatment.
Austin said despite lifesaving efforts performed by all emergency services involved, the child was pronounced dead.
"Many of us at the Plymouth Police Department have children of our own and cannot imagine what loved ones are feeling," Austin said. "We send our deepest condolences to the child’s family, and we ask that you respect their privacy during this difficult time."
The Office of the Chief Medical Examiner has not yet determined the official cause of death.
The investigation is ongoing.
This is a developing story. Check back to Daily Voice for updates.
Click here to follow Daily Voice Trumbull-Monroe and receive free news updates.