Authorities, meanwhile, on Monday will take up the issue of whether the blaze was worse than it needed to be because of low water pressure.
At one point, Sunday's fire was two city blocks wide, and low water pressure forced firefighters to get reserves from lakes and ponds on the property. The blaze was contained to the lot, but burned for more than 12 hours before the final flames were extinguished.
"The water pressure situation was a challenge," Los Angeles County Fire Chief Michael Freeman said. "This fire moved extremely fast."
County Supervisor Zev Yaroslavsky said authorities would investigate the water problems to see if they reflect a larger shortfall in the area, which is part of his district.
"There's no question that there was a lack of adequate water pressure at least in the perception of a lot of firefighters," he said. "We're going to find out what the problem was."
Sunday's fire destroyed the courthouse square from "Back to the Future" and a streetscape featured in "Bruce Almighty," "Spiderman 2" and "Transformers."
CBS News reporter Ben Tracy reported that Hollywood production lots tend to pose a significant fire risk, due to the vast amounts of wood, paint and other chemicals that are used to construct sets.
The same back lot where Sunday's fire started was the scene of a previous blaze in 1990, Tracy added. That fire also destroyed New York city street facades and part of the King Kong set.
This time around, thousands of videos chronicling Universal's movie and TV shows were destroyed in the blaze.
But Universal officials said that they were thankful no one was seriously injured at the theme park and that the damaged footage can be replaced.
"We have duplicates of everything," said NBC Universal President and Chief Operating Officer Ron Meyer. "Nothing is lost forever."
Universal officials didn't immediately say what their future plans would be for the site.
The blaze broke out on a sound stage featuring New York brownstone facades around 4:30 a.m. at the 400-acre property, Los Angeles County Fire Chief Michael Freeman said.
The cause of the fire is under investigation. Damage estimates were not available, but costs are expected to move into the millions.
Concerns for air quality due to the acrid smoke and a request from fire officials prompted the South Coast Air Quality Management District to send a chemist to take air samples at the scene, said spokesman Sam Atwood. Results were expected Monday morning.
Along with the courthouse square, the famous clock tower that enabled Michael J. Fox's character to travel through time was damaged, fire officials said. Two mock New York and New England streets used both for movie-making and as tourist displays were a total loss, Los Angeles County Fire Inspector Darryl Jacobs said.
An exhibit housing a mechanically animated King Kong that bellows at visitors on a tram also was destroyed.
All three sites were either damaged or destroyed during another fire at Universal Studios in November 1990. That fire caused $25 million in damage and was started by a security guard who was sentenced to four years in prison after pleading guilty to arson.
Sunday's fire broke out along New York Street, where firefighting helicopters swept in for drops and cranes dumped water on the flames.
The city streetscape has recently served as a backdrop in television shows like "Monk," "Crossing Jordan" and "House," said NBC Universal spokeswoman Cindy Gardner.
A set used for the Clint Eastwood-directed movie "Changeling" featuring Angelina Jolie also was destroyed, Meyer said.
A thick column of smoke rose thousands of feet into the air and could be seen for miles.
"It looked like a disaster film," said Los Angeles City Councilman Tom LaBonge.
The blaze was believed to be one of the longest-running commercial fires in Los Angeles County history.
"It is one of the longest fires to extinguish because of its complexity and size," said county Fire Capt. Mike Brown.
Ten people - nine firefighters and a sheriff's deputy - suffered minor injuries in the blaze. The deputy and a firefighter were injured in an explosion in the building where the videos were housed at around 2:30 p.m., authorities said.
Meyer estimated there were 40,000 to 50,000 videos and reels in a video vault that burned but said duplicates were stored in a different location. Firefighters managed to recover hundreds of titles.
The videos included every film that Universal has produced and footage from television series including "Miami Vice" and "I Love Lucy."
Hundreds of visitors who waited for hours outside the park gates were turned away after officials decided not to open the area. On a typical weekend day, about 25,000 people visit Universal Studios.
Universal CityWalk, an adjacent shopping promenade, was also closed.
The MTV Movie Awards, broadcasting live Sunday night from the nearby Gibson Amphitheater, went on as planned.
In a statement, NBC Universal said it would reopen the theme park Monday at 10 a.m.
Universal Studios, nine miles north of downtown Los Angeles, has thrill rides and a back lot where movies and television shows are filmed, including scenes from "War of the Worlds," "When Harry Met Sally" and "Scrubs."