Officials have identified the deceased man as Ross Lehmberg, 25, originally of San Antonio, but has a recent address of Bryan.
Montgomery County deputy constables say 49 people were on the party barge Saturday night. They're a group from Texas A&M.
Around 8:40pm, they say Lehmberg jumped from the top deck, but hit the bottom deck and fell into the water. Friends jumped in to search for him and called 911.
A dive team found him around 12:30am Sunday.
"It was an accident. There's a possibility that alcohol was involved. We're still investigating that," said Lt. Tim Cade with Montgomery County Precinct 1. "JP Judge Wayne Mack was called to the scene. During the inquest, he did order an autopsy."
Deputies say the party deck boat had all the proper safety equipment and was well under capacity Passengers had signed waivers before boarding.