According to TMZ, the Ventura County Medical Examiner's Office revealed that they had to use Naya's dental records in order to confirm her identity.
The autopsy has now been completed and it has been confirmed that she died by drowning.
The website added: "Officials say the autopsy findings are consistent with a drowning and the condition of the body is consistent with the time that she was submerged."
"There is no indication from the investigation or examination that drugs or alcohol played a role in the decedent’s death, but specimens will be submitted for toxicology testing."
Ventura County Sheriff Bill Ayub revealed at the scene that there was nothing to indicate foul play or that she had taken her own life. It was simply a tragic accidental drowning.
He said that the current was very strong the day Naya went missing and that the boat Naya and her son had rented hadn't been anchored when they went for a swim.
Naya’s son, Josey, said the pair went swimming and he was helped back up on to the boat by his mum, “who boosted him on to the deck from behind”.
“He told investigators that he looked back and saw her disappear under the surface of the water.”
The Sheriff speculated: "Perhaps the boat started drifting, it was unanchored and that she mustered enough energy to get her son back on to the boat but not enough to save herself."
Josey was found a few hours later by a leasing agent, after Naya failed to return the boat.
He was wearing his life jacket and wrapped in a towel. An adult-sized life jacket was found on the boat.
Search crews found the body floating in the northeast area of the lake and the county medical examiner was notified, authorities said on Monday.
Naya played singing cheerleader Santana Lopez for six seasons on the Fox musical comedy Glee.
She had experience boating on the lake in Los Padres National Forest, authorities said.