Police and firefighters found Caleb Thomas Schwab in the pool at the end of the ride on Sunday, police said. The circumstances of the boy's death are still being investigated, police said.
Caleb was the son of Rep. Scott Schwab and his wife, Michele, who issued a statement Sunday night.
"Since the day he was born, he brought abundant joy to our family and all those who he came into contact with," the parents said. "As we try and mend our home with him no longer with us, we are comforted knowing he believed in his savior, Jesus, and they are forever together now. We will see him another day."
Kansas state police are investigating Caleb's death at the Schlitterbahn water park, which has been closed for the investigation, said spokeswoman Winter Prosapio.
The boy died while riding the Verrückt, the world's tallest water slide, she said. The park has released no other details into how the boy died.
The slide requires two to three riders to be strapped in a raft with a total weight between 400 and 500 pounds. The raft then "will slide down a jaw-dropping 168 foot 7 inch structure, only to be blasted back up a second massive hill and then sent down yet another gut wrenching 50 foot drop for the ultimate in water slide thrills," the park's website says.
Caleb Schwab was riding with two adult women, to whom he was not related, police said. The women suffered minor facial injuries, police said. It was unclear whether the party met the weight requirement.
Police declined to comment further on the investigation.
Some park guests say the slide's harness wasn't working properly earlier in the day.
"A lady in front of me said that multiple times she rode the ride today, the Verruckt, and that the front harness did not work any of the times that she rode it," park guest Jessica Lundquist told KSHB.
Verrückt riders are required to be at least 54 inches tall, according Schlitterbahn's website
. It was not immediately known whether Caleb met the height requirement.
Leslie Castaneda was at the park Sunday and told CNN affiliate KMBC
that the victim's brother saw what happened.
"The little boy said to a worker, 'I just saw my little brother die because of one of your attractions,'" Castaneda told KMBC
. "(Caleb) looked skinny. He shouldn't have been on that ride."
Thousands injured annually at amusement parks
Thousands of children are hurt annually on amusement rides, according to a 2013 study
by Nationwide Children's Hospital in Columbus, Ohio, which examined data from the Consumer Product Safety Commission.
Head and neck injuries were the most common at 28%, with 1.5% of the injuries requiring hospitalization, the study said.
Consumer Product Safety Commission statistics for 2015 are not available, but a review of the raw data found 45,000 injuries associated with amusement rides and water slides nationwide
. About 30,000 of these cases involved those under age 18.
Verrückt, trouble from the start?
At 17 stories high -- higher than Niagara Falls -- Verrückt propels riders at 50 mph. Its name translates as "insane" in German.
Standing at exactly 168 feet 7 inches, the slide was certified by Guinness World Records in May 2014 as the world's tallest water slide. It is 5 feet taller than the previous record holder, a water slide at a Rio de Janeiro country club.
The slide opened to the public in July 2014 after several weeks of delays. Technical glitches forced the original May 23 opening date to be pushed back three times, a park spokesperson told CNN at the time.
"We always ride our rides first," Schooley said. "And we found out it was too steep and too short. So we were able to redesign it from what we learned. We tore down two-thirds of the slide and rebuilt it into the design we have now."
The slide will remain closed during the investigation, Schlitterbahn said in a statement.