Police and Unified Fire Authority arrived within minutes and took him to Intermountain Medical Center in critical condition, but he died later that afternoon, Ford said.
An autopsy was performed Monday.
Police continued to investigate, although Ford said there was nothing to suggest negligence or foul play.
"We want to know if there is anything to be learned from this," Ford said.
It was not known how long the boy was under the water before being discovered, but Ford said it appeared to have been "a very short time."
The officer did not know if the boy was able to swim or not.
Mike Peterson, director of the Cottonwood Heights Recreation Service Area, said that almost simultaneously someone saw the boy and was yelling as a lifeguard independently spotted the victim and was heading into the pool.
Peterson, who said the center was doing its own internal verification of what happened, said the boy had come to the center that day with his father.
Ford confirmed the boy was there with family, but added: "We don't know where his parents were when this occurred."
The officer said there were "several hundred" people in or around the pool at the time.
Peterson said there 730 people were admitted to the center Sunday, according to attendance records.
He said there were 20 lifeguards on duty Sunday, although only 14-15 were pool-side at the time the boy was spotted because they rotate every 15 minutes.
Peterson said the pool was open on Monday, but a different crew of lifeguards was on duty.
Those who were working on Sunday will be offered grief counseling and will take at least 24 to 48 hours off before returning to work, Peterson said, adding that the staff of 110 are mostly high school and college students.
Both Peterson and Ford called the drowning a tragic event.
"We want everyone to be vigilant, be aware," Ford said, regarding swimming pool patrons. "If you see something, call it to the attention of a lifeguard."