Authorities said the "extremely remorseful" man admitted to accidentally starting the fire Thursday when he improperly discarded fireplace ashes at his home south of town.
The fire was fueled by 82-mph wind gusts, burning 3,200 acres, and forcing thousands from their homes
"There is nothing left in some of those places except for the chimneys and fireplaces," said Gov. Brian Sandoval.
Rain and snow helped firefighters surround the brush fire. Fire officials declared the blaze contained early Saturday and lifted all remaining evacuations.
The next challenge for emergency workers may be a storm in the Sierra Nevada, which could create headaches for officials who fear its potential for causing flooding in burned areas.
The district attorney's office said they will determine whether criminal charges should be filed against the man.
In addition to the potential for facing jail time on arson charges, the man could also be ordered to pay the cost of fighting the fire, which already totals $690,000 and could run into millions of dollars.
The Associated Press contributed to this story.