San Diego Boating Under the Influence Lawyers (HN 655)

BUI charges on San Diego waterways carry up to 6 months in jail and thousands in fines. If injury or death is involved, you’re looking at felony prison time. Our defense lawyers know how to fight these cases. Call 24/7.

A BUI charge in San Diego changes everything about what was supposed to be a day on the water. Most people charged with boating under the influence never saw it coming. A routine safety inspection on Mission Bay turns into a field sobriety test on a rocking dock, and suddenly you’re in handcuffs while your family watches from the boat.

This charge doesn’t define who you are. We’ve defended clients who were pulled over during holiday enforcement sweeps on Mission Bay, stopped during routine Harbor Police patrols on San Diego Bay, and contacted by Fish and Wildlife wardens at inland lakes throughout the county. These are professionals, parents, and responsible adults who made a judgment call that law enforcement disagreed with.

Charges are accusations, not convictions. The prosecution still has to prove every element beyond a reasonable doubt, and BUI cases present unique defense opportunities that simply don’t exist in standard DUI cases. Field sobriety tests that were never designed for marine environments. Breath testing devices affected by wind, spray, and temperature. Environmental conditions like sun exposure and dehydration that mimic the very symptoms officers are trained to look for.

At David P. Shapiro Criminal Defense Attorneys, we’ve defended clients facing BUI and DUI charges throughout San Diego County. We know the Harbor Police enforcement patterns on Mission Bay. We know how these cases move through the Central Courthouse downtown, the Vista Courthouse, and El Cajon. We know what it takes to challenge these charges effectively.

Time matters. Early action creates options that disappear later. Evidence fades, witnesses forget, and the window for the strongest defense is now.

Quick Reference: HN 655 Boating Under the Influence

Classification	Misdemeanor (standard); Felony if causing serious bodily injury or death
First Offense BUI	Up to 6 months county jail, up to $1,000 fine (plus penalty assessments)
Second Offense BUI (within 7 years)	Up to 1 year county jail, up to $1,000 fine (plus penalty assessments)
BUI Causing Great Bodily Injury	Felony: 16 months, 2 years, or 3 years state prison
DMV License Suspension	No — BUI does not trigger DMV administrative action
Strike Offense	No (standard BUI); possible if felony BUI with personally inflicted GBI
Additional	Implied consent for chemical testing under HN § 655.1

What Is Boating Under the Influence Under California Law?

Harbors and Navigation Code Section 655 is California’s primary BUI statute. It is structurally similar to Vehicle Code Section 23152 (the standard DUI law) but applies specifically to operating vessels on California waterways.¹

The statute prohibits several distinct types of conduct:

BUI (alcohol) under Section 655(b) makes it unlawful to operate any vessel or manipulate water skis, an aquaplane, or a similar device while under the influence of an alcoholic beverage.²

BUI (drugs) under Section 655(c) covers operation while under the influence of any drug.³

BUI (combined) under Section 655(d) covers operation while under the combined influence of alcohol and any drug.⁴

Per se BUI under Section 655(e) makes it unlawful to operate a recreational vessel with a blood alcohol concentration of 0.08% or more by weight.⁵ This is the “per se” violation. The prosecution doesn’t need to prove you were actually impaired, only that your BAC hit 0.08%.

Commercial vessel BUI under Section 655(f) sets a lower threshold of 0.04% BAC for operators of commercial (non-recreational) vessels.⁶

What does “under the influence” actually mean? It means your physical or mental abilities were impaired to such a degree that you no longer had the ability to operate a vessel with the caution characteristic of a sober person of ordinary prudence under the same or similar circumstances.⁷ That’s the legal standard, and it’s more subjective than most people realize. The prosecution has to prove impairment, not just that you had a drink.

One critical distinction worth understanding right away: “operating” a vessel is broader than “driving” a car. It includes steering, navigating, or being in actual physical control of the vessel. But being intoxicated on a boat is not itself illegal. Passengers can lawfully drink on recreational vessels in California. The law only applies to the person operating or manipulating the vessel.

What Must the Prosecution Prove?

To convict you of BUI under Section 655(b), the prosecution must prove ALL of the following beyond a reasonable doubt:⁸

1. You operated a vessel (or manipulated water skis, an aquaplane, or similar device).

The prosecution has to establish that you were actually in control of the vessel. Were you steering? Were you at the helm? Or were you a passenger who happened to be near the controls? If you were anchored, not underway, and not in actual physical control, this element may not be met. Being drunk on a boat is not the same as operating a boat while drunk.

2. You were on the waters of this state.

This covers all waters within California’s jurisdiction: bays, harbors, inland lakes, reservoirs, rivers, and coastal waters. In San Diego, that includes Mission Bay, San Diego Bay, and every inland lake from Miramar to El Capitan.

3. You were under the influence of an alcoholic beverage.

This is where the real fight happens. The prosecution must prove your abilities were actually impaired to the degree described above. Smelling like alcohol isn’t enough. Having bloodshot eyes after eight hours in the sun isn’t enough. They need evidence of genuine impairment.

For the per se violation under Section 655(e), the elements are slightly different:⁹

1. You operated a recreational vessel (or manipulated water skis, aquaplane, or similar device);

2. On the waters of this state;

3. While having a blood alcohol concentration of 0.08% or more by weight.

The burden is on them to prove all of this. Beyond a reasonable doubt. That’s a high bar, and every element is a potential avenue for defense.

BUI vs. DUI: Key Differences That Matter

What does BUI look like compared to a standard DUI? The differences are significant, and understanding them is essential to building an effective defense.

No DMV License Suspension

This is the single biggest practical difference between BUI and DUI, and it’s the one most people don’t know about. A standard BUI conviction does not trigger a DMV administrative hearing and does not result in suspension of your driver’s license.¹⁰ There is no “admin per se” process like there is with a DUI under Vehicle Code Section 23152.

For all intents and purposes, your ability to drive to work, take your kids to school, and go about your daily life remains intact after a BUI charge. That’s a major distinction from DUI, where you can lose your license before you’re ever convicted of anything.

The exception: if you were also driving a vehicle to or from the boat launch while impaired, you could face a separate DUI charge under the Vehicle Code, which would trigger the DMV process. But the BUI itself does not.

Open Containers Are Legal on Boats

Unlike California’s strict open container laws for vehicles, there is no general prohibition against open containers on recreational vessels.¹¹ Passengers can lawfully drink alcohol on boats. This matters for your defense because the mere presence of alcohol on the vessel, open containers, or evidence that people were drinking doesn’t prove the operator was impaired.

Different Enforcement Procedures

BUI enforcement involves different agencies, different protocols, and different constitutional considerations than roadside DUI stops. On the water, you’re dealing with San Diego Harbor Police, U.S. Coast Guard, California Department of Fish and Wildlife wardens, or county sheriff’s deputies. The way they initiate contact, conduct investigations, and administer testing differs from a standard traffic stop, and those differences create defense opportunities.

Comparison at a Glance

Factor	DUI (VC 23152)	BUI (HN 655)
BAC Threshold (Standard)	0.08%	0.08% (recreational vessel)
BAC Threshold (Commercial)	0.04%	0.04%
DMV License Suspension	Yes — automatic admin per se hearing	No
Open Container	Illegal in vehicle	Legal on recreational vessel
Field Sobriety Tests	NHTSA-validated for roadside use	Not validated for marine environment
Primary Enforcing Agency	CHP, local police	Harbor Police, Coast Guard, CDFW
Implied Consent	Yes (VC § 23612)	Yes (HN § 655.1)

Penalties and Consequences

Now let’s walk through what you’re actually facing. The penalties depend on whether this is a first offense, a repeat offense, or whether anyone was injured.

First Offense BUI (Misdemeanor)

Penalty	Range
Jail	Up to 6 months in county jail
Fine	Up to $1,000 base fine (penalty assessments can multiply this 4-5x)
Probation	Up to 3 years informal/summary probation
Education	Court may order alcohol/drug education program
Boating Safety	May be required to complete a boating safety course

Second Offense BUI (Within 7 Years)

Penalty	Range
Jail	Up to 1 year in county jail
Fine	Up to $1,000 base fine (plus penalty assessments)
Probation	Up to 5 years informal probation

BUI Causing Great Bodily Injury or Death (Felony)

This is where the stakes escalate dramatically. Under Harbors and Navigation Code Section 655.6, BUI causing great bodily injury is a felony.¹²

Penalty	Range
Classification	Felony
Prison	16 months, 2 years, or 3 years in state prison
GBI Enhancement	Additional 3 to 6 years consecutive (PC § 12022.7)
Fine	Up to $5,000 (plus penalty assessments)

If a BUI results in death, the prosecution may also file charges under Penal Code Section 191.5 for vehicular manslaughter while intoxicated, which carries even more severe consequences.¹³

Prior DUI and BUI Cross-Counting

Here’s something many people don’t realize: prior DUI convictions under Vehicle Code Section 23152 may count as priors for purposes of BUI sentencing enhancement, and vice versa.¹⁴ So if you have a prior DUI on your record and you’re now facing a BUI, the prosecution may treat this as a second offense with enhanced penalties.

Implied Consent and Chemical Test Refusal

Under Harbors and Navigation Code Section 655.1, California’s implied consent law applies to boating.¹⁵ If you are lawfully arrested for BUI, you are deemed to have consented to chemical testing (breath or blood) to determine your BAC. Refusing to submit to testing can result in additional penalties and can be used as evidence against you at trial.

San Diego BUI Enforcement: What You Need to Know

San Diego is one of the most active BUI enforcement areas in California. Understanding how and where enforcement happens helps you understand the defense opportunities in your case.

Mission Bay: Ground Zero for BUI Arrests

Mission Bay is the highest BUI enforcement area in San Diego County. San Diego Harbor Police patrol Mission Bay aggressively, particularly during holiday weekends. July 4th, Memorial Day, and Labor Day weekends see saturation patrols and organized BUI enforcement operations.

Every year, San Diego Harbor Police participates in Operation Dry Water, a national BUI enforcement campaign typically conducted around the Fourth of July weekend. During these operations, officers are specifically looking for impaired boaters and will conduct heightened numbers of safety inspections that can quickly turn into BUI investigations.

Other Enforcement Areas

San Diego Bay sees regular Harbor Police and Coast Guard enforcement. Inland lakes including Lake Miramar, Lake Murray, Lake Hodges, and El Capitan Reservoir are patrolled by California Department of Fish and Wildlife wardens and county sheriff’s deputies. Oceanside Harbor has its own harbor unit conducting enforcement in North County.

Where Your Case Will Be Heard

BUI cases in San Diego County are heard at different courthouses depending on where the arrest occurred:

• Mission Bay / San Diego Bay: Central Courthouse, 1100 Union Street, San Diego
• North County (Oceanside Harbor): Vista Courthouse, 325 S. Melrose Drive, Vista
• East County lakes: El Cajon Courthouse, 250 E. Main Street, El Cajon
• South Bay: Chula Vista Courthouse, 500 Third Avenue, Chula Vista

How BUI Stops Work on the Water

BUI enforcement on the water differs from a standard traffic stop in important ways. Officers may initiate contact through a “safety inspection,” checking for required safety equipment like life jackets, fire extinguishers, and registration. During that inspection, if they observe signs of impairment (odor of alcohol, slurred speech, bloodshot eyes), the encounter can escalate into a BUI investigation.

The constitutional question is whether that escalation was lawful. A routine safety inspection has different legal parameters than a detention based on reasonable suspicion. How the officer transitioned from a safety check to a BUI investigation matters enormously for your defense.

Defense Strategies for BUI Charges

BUI cases present defense opportunities that don’t exist in standard DUI cases. The marine environment, the enforcement procedures, and the science behind the testing all create avenues to challenge the prosecution’s case. Let’s walk through the approaches we consider.

Field Sobriety Tests Were Never Designed for Water

This is one of the strongest defense angles in any BUI case. The standardized field sobriety tests (walk-and-turn, one-leg stand, horizontal gaze nystagmus) were developed and validated by the National Highway Traffic Safety Administration for use on flat, dry, well-lit surfaces.¹⁶ They were never validated for marine environments.

What does that look like in practice? An officer asks you to perform a walk-and-turn test on a floating dock that’s moving with the wake. Or on a boat deck. Or on a sandy shore after you’ve been on the water for six hours. Your balance is already affected by hours of wave motion (“sea legs”), sun exposure, wind, and physical activity. The test results under those conditions are, for all intents and purposes, meaningless from a scientific standpoint.

We can, and will, challenge the reliability of field sobriety test results if the facts support a position to do so. The conditions under which these tests were administered matter as much as the results themselves.

Environmental Factors That Mimic Impairment

Spend eight hours on a boat in the San Diego sun and you’ll exhibit many of the same symptoms officers associate with alcohol impairment. Red, watery eyes. Unsteady balance. Flushed skin. Fatigue. Slurred speech from dehydration. Disorientation.

None of those symptoms require a single drop of alcohol. Sun exposure, dehydration, physical exertion from swimming or wakeboarding, seasickness, and wind exposure can all produce the exact indicators officers are trained to identify as signs of impairment. An experienced defense attorney knows how to present this evidence effectively and force the prosecution to distinguish between actual impairment and normal effects of a day on the water.

Challenging the Initial Contact and Detention

The Fourth Amendment still applies on the water. While law enforcement may conduct routine safety inspections of vessels, the legality of how that inspection escalated into a BUI investigation is frequently at issue.

Officers need reasonable suspicion of criminal activity to detain you beyond a brief safety check. If the only indicator was the odor of alcohol, without observable impairment or unsafe operation, the detention may have been unlawful. And if the detention was unlawful, the evidence obtained as a result may be suppressed. That means the jury never sees it.

Challenging the Chemical Test Results

Breath testing on the water presents unique reliability problems. Portable breath testing devices used on patrol boats or docks can produce inaccurate results due to wind, water spray, temperature fluctuations, and other environmental conditions. California Code of Regulations, Title 17, governs chemical testing procedures, and deviations from those required protocols can render results inadmissible or unreliable.¹⁷

For blood testing, we examine chain of custody, proper storage, and potential fermentation of blood samples. We also look at the timing of the test relative to when you were actually operating the vessel.

Rising Blood Alcohol Defense

If there was a significant delay between when you were operating the vessel and when the chemical test was administered, your BAC at the time of operation may have been below 0.08%. Alcohol continues to absorb into the bloodstream after you stop drinking. A BAC of 0.09% at the testing station an hour after the stop could easily have been 0.07% at the time you were actually on the water. The prosecution has to prove your BAC at the time of operation, not at the time of testing.

You Weren’t Operating the Vessel

The prosecution must prove you were actually operating or manipulating the vessel. If you were a passenger, if the boat was anchored and you were not underway, or if someone else was at the helm, this element fails. Remember: being intoxicated on a boat is not a crime. Operating a boat while intoxicated is. That distinction matters.

Mouth Alcohol and Medical Conditions

Gastroesophageal reflux disease (GERD), acid reflux, or recent vomiting can cause residual mouth alcohol that artificially inflates breath test results. Officers are required to observe a 15-minute waiting period before administering a breath test to ensure mouth alcohol has dissipated. In the chaos of a waterway BUI investigation, that observation period is sometimes cut short or not properly documented.

Related Charges: Understanding the Differences

BUI charges don’t exist in a vacuum. Several related offenses may come into play depending on the facts of your case.

Reckless Operation (HN § 655(a))

Harbors and Navigation Code Section 655(a) prohibits operating a vessel in a reckless or negligent manner that endangers the safety of others.¹⁸ This is not an alcohol-specific offense and can serve as a plea bargain target, similar to a “wet reckless” reduction in DUI cases. A reduction to reckless operation avoids the BUI conviction on your record while still resolving the case.

DUI (VC § 23152)

If you drove a vehicle to or from the boat launch while impaired, you could face a separate DUI charge under the Vehicle Code in addition to the BUI.¹⁹ This is a common scenario and significantly changes the stakes because a DUI triggers DMV administrative proceedings and potential license suspension that a BUI alone does not.

Child Endangerment (PC § 273a)

If minor passengers were on the vessel, the prosecution may add child endangerment charges under Penal Code Section 273a.²⁰ This is a wobbler offense that can be charged as either a misdemeanor or a felony depending on the circumstances.

Vehicular Manslaughter While Intoxicated (PC § 191.5)

In the most serious cases where a BUI results in death, the prosecution may file vehicular manslaughter charges under Penal Code Section 191.5.²¹ This carries substantially more severe penalties than standard BUI and may qualify as a strike offense.

Facing BUI Charges in San Diego?

BUI cases in San Diego involve enforcement agencies, testing protocols, and environmental conditions that most criminal defense attorneys rarely encounter. We’ve defended clients arrested during Mission Bay holiday enforcement operations, stopped by Harbor Police on San Diego Bay, and contacted by Fish and Wildlife wardens at inland lakes throughout the county. We know the unique defense opportunities these cases present, from challenging field sobriety tests that were never designed for marine environments to questioning the reliability of breath testing conducted on the water. You’re entitled to a defense that matches the specifics of what you’re facing.

Every day without representation is a day the prosecution works unopposed.

Call us 24/7 for a consultation. We’ll review the facts of your case, explain exactly what you’re up against, and lay out your options. The bottom line is this: BUI charges are defensible, and the sooner we start building that defense, the more options you have. Contact our San Diego defense team today to protect your freedom and your future. You must know your rights.

References

1. 1. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
2. 2. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
3. 3. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
4. 4. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
5. 5. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
6. 6. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
7. 7. See CALCRIM No. 2100 [Boating Under the Influence].↑ See CALCRIM No. 2100 [Boating Under the Influence].
8. 8. See CALCRIM No. 2100 [Boating Under the Influence].↑ See CALCRIM No. 2100 [Boating Under the Influence].
9. 9. See CALCRIM No. 2101 [Boating With 0.08 Percent Blood Alcohol].↑ See CALCRIM No. 2101 [Boating With 0.08 Percent Blood Alcohol].
10. 10. See Harbors and Navigation Code, § 655 (no provision for DMV administrative action); cf. Vehicle Code, § 23152 (DMV administrative per se hearing).↑ See Harbors and Navigation Code, § 655 (no provision for DMV administrative action); cf. Vehicle Code, § 23152 (DMV administrative per se hearing).
11. 11. See Harbors and Navigation Code, § 655 (no provision for DMV administrative action); cf. Vehicle Code, § 23152 (DMV administrative per se hearing).↑ See Harbors and Navigation Code, § 655 (no provision for DMV administrative action); cf. Vehicle Code, § 23152 (DMV administrative per se hearing).
12. 12. Harbors and Navigation Code, § 655.6.↑ Harbors and Navigation Code, § 655.6.
13. 13. Penal Code, § 191.5 [Gross vehicular manslaughter while intoxicated].↑ Penal Code, § 191.5 [Gross vehicular manslaughter while intoxicated].
14. 14. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
15. 15. Harbors and Navigation Code, § 655.1 [Implied consent for chemical testing].↑ Harbors and Navigation Code, § 655.1 [Implied consent for chemical testing].
16. 16. See National Highway Traffic Safety Administration, DWI Detection and Standardized Field Sobriety Testing (NHTSA Manual) (field sobriety tests validated for roadside conditions only).↑ See National Highway Traffic Safety Administration, DWI Detection and Standardized Field Sobriety Testing (NHTSA Manual) (field sobriety tests validated for roadside conditions only).
17. 17. See California Code of Regulations, Title 17, § 1215-1222.1 [Chemical testing procedures].↑ See California Code of Regulations, Title 17, § 1215-1222.1 [Chemical testing procedures].
18. 18. Harbors and Navigation Code, § 655.↑ Harbors and Navigation Code, § 655.
19. 19. Vehicle Code, § 23152.↑ Vehicle Code, § 23152.
20. 20. Penal Code, § 273a [Child endangerment].↑ Penal Code, § 273a [Child endangerment].
21. 21. Penal Code, § 191.5 [Gross vehicular manslaughter while intoxicated].↑ Penal Code, § 191.5 [Gross vehicular manslaughter while intoxicated].