Operating a boat while under the influence of drugs or alcohol (BUI), also called “boating while intoxicated” (BWI), is illegal in all 50 states. There are two types of BUI: Those based on excessive blood alcohol concentration (BAC) and those involving proof of actual impairment. In almost every state, you can get a BUI for boating with a BAC of .08% or more. (Only two states—North Dakota and Wyoming—have a higher BAC limit of .1%.) And the laws of all states prohibit operating a watercraft while actually impaired by drugs, alcohol, or a combination of the two. The details of BUI laws, however, vary by state.
Read about the consequences of a BUI/BWI conviction in your state.