Possible Defenses to an Arizona OUI Charge

Defending against an Arizona boating-under-the-influence charge.

By Josh Egan

Arizona law prohibits operating or being in actual physical control of a motorized watercraft while under the influence (OUI) of drugs or alcohol. Arizona's OUI statute is nearly identical to its DUI counterpart, so some of the same defenses apply to both charges.

A boater can be charged with OUI for operating a watercraft while:

  • impaired to the “slightest degree” by drugs or alcohol, often called an “impairment” OUI
  • having a blood alcohol concentration (BAC) of .08%  or greater within two hours of boat operation, commonly referred to as a “per se” OUI, or
  • having any amount of a drug in the body, a per se drug OUI.

Generally, the available defenses depend on which type of BUI the boater is charged with. (Ariz. Rev. Stat. Ann. § 5-395 (2016).)

Valid Prescription

When a boater is charged with OUI based on drug use, is having a valid prescription for the drug a defense? It depends.

If someone is charged with a drug-related impairment OUI, having a prescription for the drug isn’t a defense. In other words, a boater who was taking a drug legally can still be convicted of an OUI if the drug impaired the boater’s ability to operate a watercraft.

The outcome is different, however, when a person is charged with a per se drug OUI—a valid prescription for the drug is a complete defense to the charge. At first glance, this may appear like an easy out for boaters who get behind the helm after taking a prescription drug—not so. Most prosecutors will file two charges against someone suspected of boating while under the influence of drugs: a per se drug charge and one based on impairment. So even if the prescription can be used to beat the per se charge, it won’t help with impairment allegations.   

Timing of the BAC Measurement

In many states, an alcohol per se OUI/DUI requires proof that the person’s BAC was above the legal limit at the time of operating or driving. Because a person’s BAC is constantly changing—either rising or falling—defendants in these states often argue the “rising blood alcohol defense.” Arizona law, on the other hand, only requires the state to prove a person's BAC was above the limit within two hours of operating the watercraft. This rule effectively takes the rising BAC defense off the table.  

However, the two-hour rules doesn’t eliminate all possible defenses to a per se OUI charge. For example, if police show up to a boating accident after it occurred, the prosecution might have difficulty meeting its burden of proof. In other words, without a witness to say when the collision occurred, the state may have problems establishing that the person's BAC was .08% or greater within two hours of operating the watercraft.

(For more on the law, see Arizona's Operating a Watercraft Under the Influence Laws. And Arizona OUI Penalties discusses the consequences of OUI convictions.)    

Talk to an Attorney

If you’ve been arrest for or charged with boating under the influence, get in contact with an experienced attorney who handles OUI cases. A qualified lawyer can help you understand how the law applies to the fact of your case and what your available defenses are. 

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