Officials tell us Klein was charged with one count of DUI with a prior ... and one count of driving with a .08 blood alcohol level or higher. And boy was he higher ...
Law enforcement sources tell us Klein took two breathalyzer tests on the morning he was arrested ... registering a .22 and a .24. The latter is THREE TIMES the legal limit.
If convicted, Klein faces a mandatory minimum of 96 hours in county jail -- but could be sentenced to serve up to one year behind bars. He could also be ordered to pay a $1,000 fine plus some serious penalties.
As we first reported, Klein was arrested on June 16 when a CHP officer noticed his car swerving on the 101 Freeway in Los Angeles at 3:13 AM ... with his dog in the car.
Klein has since checked into a rehab clinic in Utah.