Boating under the influence in California is a criminal offense under Harbors and Navigation Code Section 655. The recreational limit is a blood alcohol concentration of 0.08 percent, the same threshold that applies to drivers, and the law reaches nearly every kind of watercraft, including kayaks, canoes, and paddleboards. A first offense is a misdemeanor punishable by up to six months in county jail and a $1,000 fine, and penalties climb quickly when there is an injury, a prior conviction, or a prior vehicle DUI on the record.
What Counts as BUI
Prosecutors can charge a BUI under either of two theories. The first is impairment: if alcohol, drugs, or a combination affect your ability to operate a vessel with ordinary care, you can be convicted regardless of your BAC. The second is per se: a BAC of 0.08 percent or higher while operating a recreational vessel is illegal whether or not your handling of the boat was actually affected.1California Legislative Information. California Harbors and Navigation Code 655
Commercial operators face a stricter per se limit of 0.04 percent BAC.1California Legislative Information. California Harbors and Navigation Code 655 The statute also covers anyone manipulating water skis, an aquaplane, or a similar towed device. You do not need to be at the helm of a motorboat to be charged.
Which Boats the Law Covers
The Harbors and Navigation Code defines “vessel” broadly as any watercraft used or capable of being used for transportation on water. The only exceptions are seaplanes on the water and watercraft locked onto a permanently fixed track, such as amusement park rides.2California Legislative Information. California Harbors and Navigation Code 651 Motorboats, sailboats, personal watercraft, pontoon boats, kayaks, canoes, and paddleboards all fall inside that definition. The common belief that non-motorized craft are exempt is wrong.
Underage Operators
Boaters under 21 face a near-zero-tolerance rule. Harbors and Navigation Code Section 655.6 makes it illegal for anyone under the legal drinking age to operate a vessel with a BAC of 0.01 percent or higher, mirroring the standard California uses for underage drivers under Vehicle Code Section 23140. A single drink can be enough to support a charge.
First-Offense Penalties
A first BUI without injury is a misdemeanor. Conviction carries a fine of up to $1,000, up to six months in county jail, or both.3California Legislative Information. California Code HNC 668 Most first offenders receive summary probation rather than jail, and courts often require completion of an alcohol or drug education program as a probation condition.
One thing a first BUI conviction does not do is trigger a driver’s license suspension. There is no DMV administrative per se hearing for boating offenses, so your driving record is unaffected on the administrative side. The criminal conviction still appears on background checks.
Repeat Offenses Within Seven Years
California uses a seven-year lookback window for BUI sentencing. A second or subsequent BUI conviction within seven years of an earlier one raises the maximum jail sentence to one year in county jail, with the fine remaining at up to $1,000.3California Legislative Information. California Code HNC 668
The lookback counts more than just prior BUIs. A previous vehicle DUI conviction under Vehicle Code Section 23152 or 23153, or a vehicular manslaughter conviction under Penal Code Sections 191.5 or 192.5, also triggers the enhanced penalties.3California Legislative Information. California Code HNC 668 The statute treats impaired operation as a single pattern, whether it happened on water or on the road.
When Someone Is Injured
A BUI that causes bodily injury to another person is charged under Harbors and Navigation Code Section 655(f) as a wobbler. Prosecutors can file it as either a misdemeanor or a felony depending on the severity of the injuries and the defendant’s criminal history.
As a misdemeanor, BUI causing injury carries 90 days to one year in county jail and a fine between $250 and $5,000. As a felony, the sentence is 16 months, two years, or three years in state prison under California’s triad sentencing structure, plus the same $250 to $5,000 fine.3California Legislative Information. California Code HNC 668
If a felony BUI causing injury occurs within seven years of a prior BUI or DUI conviction, the court must impose at least five days in county jail and a minimum $250 fine as conditions of any probation grant. With two or more priors, the minimum jail term as a probation condition rises to 60 days.3California Legislative Information. California Code HNC 668
Refusing a Chemical Test
Refusing to submit to a chemical test after a lawful BUI arrest is a separate infraction under the Harbors and Navigation Code. A BUI refusal does not carry an automatic driver’s license suspension, because the DMV’s administrative per se process applies only to motor vehicles. The refusal can, however, be used against you at trial as evidence of consciousness of guilt, and it can lead to enhanced sentencing if you are convicted of the underlying BUI.
How a BUI Affects a Later DUI
A prior BUI conviction counts as a prior offense when sentencing a later vehicle DUI within the lookback period, and a prior DUI counts the same way against a later BUI. The Harbors and Navigation Code cross-references Vehicle Code Sections 23152 and 23153 for exactly this purpose.3California Legislative Information. California Code HNC 668 A BUI that felt like a minor weekend matter at the time can turn a later DUI arrest into a second-offense case with mandatory jail time.
The two offenses diverge on the administrative side. A vehicle DUI triggers an immediate DMV license suspension, a separate administrative hearing, ignition interlock installation, and an SR-22 insurance filing. None of those administrative consequences follow a standalone BUI conviction. The criminal consequences, though, track each other closely, and courts treat both as part of the same pattern when sentencing repeat offenders.