Most people I talk to after a first DUI arrest have never been in a courtroom. They want to know three things: will I go to jail, will I lose my license, and what will this cost. The honest answer to all three is that it depends on how the State charged the case. I am certified in NHTSA Standardized Field Sobriety Testing, I have worked inside a local prosecutor's office, and I served as a federal law clerk, so I look at a first DUI the way the State will and then look for where its case is weak. This page walks through what Montana law actually says about a first offense. For the bigger picture, see our Missoula DUI defense page.
Impairment DUI and Per Se DUI Are Not the Same
Montana has more than one way to charge a DUI. An impairment DUI under MCA § 61-8-1002(1)(a) means driving or being in actual physical control of a vehicle while under the influence of alcohol, drugs, or both, meaning your ability to drive safely was diminished. A per se DUI is based on a number: an alcohol concentration of 0.08 or more (MCA § 61-8-1002(1)(b)), a delta-9-THC level of 5 ng/mL or more (§ 61-8-1002(1)(d)), or one of the drug levels added in 2025, such as 0.5 ng/mL of fentanyl without a valid prescription (§ 61-8-1002(1)(f)).
The difference is not academic. A person can be convicted of only one offense per incident (§ 61-8-1002(6)), and the penalties for a first offense differ depending on which one it is. Many people are charged with both, and part of my job is to see which theory the evidence actually supports.
First-Offense Penalties Under MCA § 61-8-1007
The table below shows the jail range and fine for a first conviction under each type of charge. A passenger under 16 in the vehicle roughly doubles the minimums and fines.
| First-offense charge | Jail | Fine |
|---|---|---|
| Impairment DUI, § 61-8-1002(1)(a) | 24 consecutive hours to 6 months | $600 to $1,000 |
| Per se DUI (0.08, THC 5 ng/mL, or listed drug levels) | Up to 6 months, no jail minimum | $600 to $1,000 |
| Aggravated DUI, § 61-8-1001 | 2 days to 1 year | $1,000 |
| Impairment DUI, passenger under 16 | 48 consecutive hours to 1 year | $1,200 to $2,000 |
| Per se DUI, passenger under 16 | Up to 6 months, no jail minimum | $1,200 to $2,000 |
| Aggravated DUI, passenger under 16 | 4 consecutive days to 1 year | $2,000 |
Sources: MCA § 61-8-1007(1)(a), (2)(a), and (4)(a). Where there is a mandatory minimum, it may not be served under home arrest and may not be suspended unless the judge finds that jail would pose a risk to the person's physical or mental well-being (§ 61-8-1007(1)(d)). The rest of a jail term may be suspended for up to 1 year while the person completes a chemical dependency treatment program (§ 61-8-1007(1)(e)).
The Required Assessment and Education Course
Every DUI conviction in Montana requires a chemical dependency assessment. A first conviction also requires a chemical dependency education course (MCA § 61-8-1009(1)). You may hear this course called by a program name, but the statute simply calls it a chemical dependency education course.
- If the assessment finds a moderate or severe alcohol or drug use disorder, treatment must be ordered (§ 61-8-1009(8)).
- When treatment is ordered for a first offender, the education course is not also required (§ 61-8-1009(8)).
- You pay for the assessment, course, and any treatment, and you may use health insurance (§ 61-8-1009(3)).
Your License After a First DUI
There are two separate license tracks, and people often confuse them.
- On conviction: MVD suspends your license for 6 months (MCA § 61-5-208(2)(b)(i)), starting from the date of conviction (§ 61-5-208(3)(a)). The court can recommend a probationary license, and if it does, it may require 24/7 testing or an ignition interlock as a condition (MCA § 61-8-1010(1)).
- On a refusal: refusing the evidentiary breath, blood, or oral fluid test brings a 6-month suspension for a first refusal with no probationary license (MCA § 61-8-1032(4)(a)). This runs from the date of the refusal, not a conviction.
If your license was taken at the arrest, the temporary permit takes effect 12 hours after it is issued and is valid for 5 days (MCA § 61-8-1016(4)(c)). You have 30 days from notice to petition the district court in the county of arrest to challenge a refusal suspension (MCA § 61-8-1017(1)). For a Missoula arrest, that is the Fourth Judicial District Court. Getting your license back also requires a $200 reinstatement fee (MCA § 61-2-107(1)). Our license suspension and hearings and test refusal pages go into more detail.
No Deferral, and Limited Expungement
In many misdemeanor cases a first-time offender can ask for a deferred sentence. Not for a DUI. A court may not defer imposition of sentence under the DUI penalty statutes (MCA § 61-8-1011(4)). And while Montana allows misdemeanor expungement, it is not presumed for a person with a DUI conviction (MCA § 46-18-1108). A first DUI conviction also counts as a prior for 10 years if you are charged again, which our second and third DUI page explains. That is why the first case deserves real attention rather than a quick plea.
Which Missoula Court Will Hear Your Case
A first DUI is a misdemeanor, so it is usually heard in a court of limited jurisdiction. Citations from Missoula city police go to Missoula Municipal Court. Citations from the Missoula County Sheriff's Office or the Montana Highway Patrol generally go to Missoula County Justice Court, which also runs a DUI court called ROAD Court. The State generally has 1 year after the offense to file a misdemeanor charge (MCA § 45-1-205(2)(b)).
How I Review a First-Offense DUI
Because I am certified in the same NHTSA field sobriety testing protocol that officers are trained in, I review the video and reports against how the tests are supposed to be given. Depending on the facts, I look at:
- whether the officer had a lawful basis for the stop and the arrest;
- how the field sobriety tests were given and scored;
- whether a breath result is reliable, and how a blood sample was drawn, stored, and tested;
- for a drug-based impairment charge, whether there is other competent evidence of impairment beyond the presence of a drug, which MCA § 61-8-1018(1)(a) requires;
- whether the evidence fits an impairment charge, a per se charge, or neither.
Any of these can affect whether evidence comes in and how the case may be resolved. Every case turns on its own facts.
This page explains Montana law in general as of the 2025 Montana Code Annotated. It is not legal advice about your specific case.