Most first-offense DWIs in Missouri end with probation, not jail. But some facts change that quickly, and people facing them often do not realize how different their case is from an ordinary first DWI until they are already in court.
These are the situations we treat as serious from the first phone call.
The baseline
Do you go to jail for a first DWI in Missouri?
Usually not. A first DWI is a class B misdemeanor, and the most common result is a suspended imposition of sentence (SIS) with probation.
Under RSMo 577.010, an SIS on a first DWI requires at least two years of probation. An SIS means that if probation is completed, no conviction is entered. See SIS vs. SES in Missouri for why that matters.
The rest of this page is about the facts that move a case away from that baseline.
The number
What happens with a high BAC on a Missouri DWI?
A reading of 0.15 or more can lead to mandatory jail time.
DWI court and treatment
In a circuit with a DWI court or other court-ordered treatment program, a person with 0.15 or more cannot receive an SIS unless they take part in and complete that program.
Minimum jail without an SIS
If no SIS is granted, the law requires at least 48 hours in jail for a reading of 0.15 to 0.20, and at least five days for a reading above 0.20.
Other people involved
What if there was a crash or a child in the car?
- A child in the vehicle. If anyone under 17 was in the vehicle, a first DWI becomes a class A misdemeanor instead of a class B, which raises the possible sentence to up to a year in jail.
- A crash with injuries. If a DWI driver acts with criminal negligence to cause physical injury to another person, the charge is a class D felony.
- Serious physical injury. The charge becomes a class C felony.
- A death. The charge is a class B felony, and more serious in some circumstances.
A crash, even one without injuries, also changes how prosecutors and judges view a case, and it often means more evidence: other drivers, scene photos, medical records, and sometimes a blood draw at the hospital. These cases need investigation from the start.
Your living
What does a DWI mean for a commercial driver’s license?
It can end a career, even when the arrest happened in a personal vehicle.
One-year disqualification
Under RSMo 302.755, a first DWI conviction, or a first alcohol-related enforcement contact such as an administrative suspension, disqualifies a person from driving a commercial vehicle for at least one year. It is at least three years if hazardous materials were involved.
A second one is for life
Two qualifying violations from separate incidents can lead to lifetime disqualification. That is why a CDL holder should treat the administrative license case as seriously as the criminal one.
A commercial vehicle also has a lower limit: 0.04, not 0.08.
Prior offenses
Does a prior DWI mean jail?
A prior DWI changes the case more than any other fact.
Prior and persistent offenders cannot receive an SIS, and a prior offender generally has to serve at least ten days before probation unless the court orders community service or treatment court instead. See our pages on a second offense DWI and a third offense DWI.
Answers
DWI jail questions we hear
Will I go to jail for my first DWI in Missouri?
Usually not. The most common result is a suspended imposition of sentence with at least two years of probation. A high BAC, a child in the car, a crash, or a commercial license can change that.
What is the mandatory jail time for a high BAC in Missouri?
If no SIS is granted, at least 48 hours for a reading of 0.15 to 0.20 and at least five days for a reading above 0.20, under RSMo 577.010.
Is it worse to get a DWI with a child in the car?
Yes. If a person under 17 is in the vehicle, a first DWI becomes a class A misdemeanor, which carries up to a year in jail.
Is a DWI with an injury a felony in Missouri?
Yes. Causing physical injury through criminal negligence while driving intoxicated is a class D felony. Serious physical injury is a class C felony, and a death is a class B felony or higher.
Will a DWI in my personal car affect my CDL?
Yes. A first DWI conviction or alcohol-related enforcement contact disqualifies a commercial license for at least one year, even if you were driving your own vehicle.
See also our Missouri DWI defense page, or call 573-638-8529.
Talk to us
A serious DWI needs a defense from day one.
If your case involves a high reading, a crash, a child, or a commercial license, the early decisions matter most.
Attorney advertising. The choice of a lawyer is an important decision and should not be based solely upon advertisements. This article is general information about Missouri law, not legal advice, and it does not create an attorney-client relationship. Sentences depend on the facts, your history, and the court.
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