The legal clerk and environmental activist, who Julia Roberts won an Oscar for portraying in the movie about her battle with Pacific Gas and Electric was not in a good way when a game warden spotted her.
Edwin W. Lyngar, a spokesman with the Nevada Wildlife Department she was slurring her words and acting in an intoxicated manner as she struggled with the craft on Lake Mead, just outside Boulder City.
He added that she tested above the legal limit of .08 blood alcohol content and was held in the Clark County Detention Center before bailing out.
If the case does get to court, The Challenge America with Erin Brokovitch star will certainly be able to afford a top legal team.
After proving that the water had been contaminated in the south California town of Hinkley, she secured a $333 million payout for the town's residents - the largest ever payout in a direct action lawsuit.
She is said to have received a personal bonus of $2millon, some of which she clearly spent on the boat.
"Boaters mistakenly think that boating and drinking go hand in hand," Lyngar said.
"They certainly do not. If we could keep people sober while operating, we'd have much safer waterways.