The incident took place in Middlesex County at Pattaconk Lake in the town of Chester on Sunday, July 17.
According to Environmental Conservation Police, officers responded to the lake for a report of an unresponsive man who was pulled from the water, said Will Healey, communications director for DEEP.
Officers found that a 21-year-old man had been pulled from the water and that lifesaving procedures were being performed. The man was transported to Middlesex Health Shoreline Medical Center where he was pronounced dead, Healey said.
The man has not been identified by officials pending notification of family members.
The cause and manner of death will be determined by the medical examiner's office.
EnCon Police are investigating the incident.
This is a developing story. Check back to Daily Voice for updates.
Click here to follow Daily Voice New Haven and receive free news updates.