The sheriff's office said Andrew Goll had been working on a dock in the 16000 block of North Inner Lane - a road accessed from Iowa Highway 86 near Okoboji View Golf Course.
The 30-year-old was found in water near the dock by a family member, according to authorities. He was doing work on a family-owned dock at the time.
Dickinson County authorities are still trying to determine what caused the Lakes enthusiast and former marina employee to drown. The emergency call came in at 4:28 p.m.
"No one witnessed it, but we're suspecting a medical condition possibly," said Dickinson County Sheriff Greg Baloun.
A doctor who lives in the area came to the scene and attempted life-saving measures. Goll was pronounced dead at the scene.
The sheriff's office was assisted by Spirit Lake First Responders. Lakes Regional Healthcare ambulance and paramedics also were on hand.
"The volunteers make all the difference in the world in response time and manpower," Baloun said.
Emergency crews have responded to five drownings this year in the Iowa Great Lakes.
"It just hasn't been our year," Baloun said. "In 2011, we had zero but in 2012, we've had five - there's no explanation for it."
The University of Nebraska-Lincoln graduate worked in the sales and hospitality sector while living in Des Moines.
Visitation for Andrew Goll will take place from 1-8 p.m. at Pelan Funeral Home in Tekamah, Neb. Visitation on Thursday will be held one hour prior to the service at the First Presbyterian Church in Tekamah.
He is preceded in death by his twin brother, Christopher Thomas Goll; his grandfathers, Neb. state Sen. James E. Goll and Victor W. Bartlett.
He is survived by his parents, James and Susan Goll of Omaha; his brothers, James Bartlett "J. B." Goll of Lexington, Ky., Benjamin H. Goll of Omaha, Neb.; his grandmothers, Doran L. Goll of Tekamah and Joan H. Bartlett of Omaha; many aunts, uncles, and cousins.
The family asks for memorials to be directed to Okoboji Protective Association, P.O. Box 242, Okoboji, IA, 51355; Phi Gamma Delta Educational Foundation, PO BOX 4599, Lexington, KY 40544 or Tekamah-Herman Public Schools Foundation, 234 S 13th St., Tekamah, NE 68061.