Last week, Laguna Beach Police handed over the case to the Orange County Calif. District Attorney's Office, which has not announced any formal charges yet.
"Because the case is under review, I can't discuss the details," DA spokeswoman Farrah Emami told PEOPLE. "Ultimately, we have to base our decision on the available evidence."
If Sambora is formally charged with both misdemeanors, a jail sentence is likely, legal experts say.
"Assuming Sambora was driving with over a .08 blood-alcohol level with a passenger under 14 in the car, he's looking at probable jail time," says veteran DUI lawyer Lawrence Taylor, who's not involved with the case. "But it's possible this can be plea bargained to a lesser offense, and/or he could get rehab in lieu of jail."
Sambora, 48, was arrested in Laguna Beach last month after police spotted him driving unsteadily in a Hummer. In the car was Sambora's girlfriend, Jenn Mallini, his daughter, Ava, 10 (whose mother is Sambora's ex-wife Heather Locklear), and her teenage cousin.
Since the incident, the Bon Jovi guitarist appears to be partying responsibly. Sambora was seen in Las Vegas over the weekend at the Hard Rock Hotel and Casino with a group of friends, where he drank only water, following the band's sold-out show at the MGM Grand.
"He was in really good spirits, having a really good time," said one onlooker. "He seemed happy and content."
Last year was a difficult one for the musician: In June, Sambora entered a treatment facility. In addition, he and Denise Richards broke up after dating for about a year. And last April, his divorce from Locklear was finalized while that same month, his father died of lung cancer.
Sambora's tentative arraignment is set for May 7.
His rep had no immediate comment.
Reporting by KC BAKER and JENNIFER GARCIA