Idaho DUI Laws: Penalties, BAC Limit & License (2026)

In Idaho the offense is called driving under the influence (DUI), and Idaho Code 18-8004 makes it unlawful to drive with a blood alcohol concentration (BAC) of 0.08 percent or more. A first DUI is a misdemeanor punishable by up to six months in jail, a fine of up to $1,000, and a license suspension that begins with 30 days of absolute suspension, under Idaho Code 18-8005.

This guide is part of our DUI Laws by State series.

What counts as a DUI in Idaho

Idaho's core impaired-driving statute, Idaho Code 18-8004, makes it unlawful to drive or be in actual physical control of a vehicle while under the influence of alcohol or drugs, or with a BAC of 0.08 percent or more. The statute charges the offense both ways, so a driver below 0.08 can still be convicted if the State proves impairment. Commercial drivers face a 0.04 percent limit, and drivers under 21 fall under the zero-tolerance provision in Idaho Code 18-8004(1)(d), which bars driving with a BAC of at least 0.02 but less than 0.08 percent. The 0.08 figure is the federal benchmark adopted by every state except Utah, which uses 0.05 percent, as the National Highway Traffic Safety Administration describes. A BAC of 0.20 percent or more triggers the excessive alcohol concentration penalties in Idaho Code 18-8004C, even on a first offense.

First-offense DUI penalties in Idaho (jail, fines, suspension)

A first DUI is a misdemeanor. Under Idaho Code 18-8005(1), a first offender may be sentenced to jail for up to six months and a fine of up to $1,000; there is no mandatory minimum jail term for a standard first offense at 0.08 to under 0.20 percent. The court suspends the driver's license, with the first 30 days being an absolute suspension during which no driving of any kind is allowed, followed by 60 to 150 days during which the court may grant a restricted permit. The statute also requires an ignition interlock device for one year after the suspension period ends. A first offense with a BAC of 0.20 percent or more is an excessive concentration offense under Idaho Code 18-8004C, which carries a mandatory minimum 10 days in jail and a one-year absolute suspension.

Watch out: The administrative license suspension and the criminal DUI case run on separate tracks. The Idaho Transportation Department can suspend your license based on a failed or refused test even if the criminal charge is later reduced or dismissed, and you must request the administrative hearing within the short statutory deadline.

Ignition interlock requirements in Idaho

Idaho requires an ignition interlock device on a first DUI, which sets it apart from states that reserve the device for repeat offenders. Under Idaho Code 18-8005(1), a first offender must install an interlock on every vehicle the person drives for one year following the suspension period, and the device is installed within 10 days after the absolute suspension ends. The interlock requires a breath sample before the engine starts and at random intervals during a trip, and the driver pays for installation, monthly monitoring, and removal. For second and third offenses the interlock term scales up, and an offender who seeks a restricted permit to drive during the restricted phase of a suspension generally must use the device as a condition of that permit.

License suspension and the administrative (ALS) process in Idaho

Idaho runs two suspension systems at once. The administrative track is handled by the Idaho Transportation Department under Idaho Code 18-8002A: a driver who fails the evidentiary test (0.08 percent or more) faces a 90-day suspension on a first failure, with the first 30 days absolute and a restricted permit possible afterward. The arresting officer serves a notice that also acts as a temporary permit, and the driver must request a hearing within seven days to contest the administrative suspension. A separate court-ordered suspension follows a conviction under Idaho Code 18-8005, running 30 days absolute plus 60 to 150 days. The two suspensions can overlap, but a driver must satisfy both, complete any required evaluation or treatment, and install the interlock to reinstate.

Repeat offenses and the Idaho look-back period

Idaho counts prior DUI convictions within a 10-year look-back window, so penalties climb sharply for offenses inside that period. A second DUI within 10 years under Idaho Code 18-8005(4) carries a mandatory minimum of 10 days in jail (the first 48 hours consecutive) up to one year, a fine of up to $2,000, and a one-year absolute license suspension. The felony threshold sits at the third offense: a third DUI within 10 years is a felony under Idaho Code 18-8005(6), punishable by up to 10 years in the custody of the state board of correction, a fine of up to $5,000, and a multi-year license suspension. Out-of-state DUIs from a substantially conforming law count as priors. Aggravated DUI causing great bodily harm under Idaho Code 18-8006 is a felony regardless of offense number.

Watch out: Refusing the evidentiary test does not protect your license. A first refusal triggers a one-year suspension under Idaho Code 18-8002, longer than the 90-day suspension for failing the test, and the refusal can be used as evidence and can carry its own civil penalty.

Refusing a breath or blood test in Idaho

Idaho's implied consent law, in Idaho Code 18-8002, provides that by driving in the state you have agreed to evidentiary testing of breath, blood, or urine if an officer has reasonable grounds to believe you were driving under the influence. Refusing the test results in a one-year license suspension for a first refusal and a two-year suspension for a second refusal within 10 years, along with a civil penalty and an ignition interlock requirement for one year after the suspension. Because the refusal suspension is longer than the 90-day suspension for failing the test, refusing usually makes the license consequences worse. The driver may contest the refusal suspension at a hearing requested within the statutory deadline.

Can you expunge or seal a DUI in Idaho

Idaho does not have a general expungement statute for adult criminal convictions, so a DUI conviction generally cannot be expunged or sealed in the way many other states allow. A DUI that ends in a dismissal or acquittal does not produce a conviction record, and a misdemeanor that was withheld and later dismissed after probation may be set aside, but a completed DUI conviction typically stays on the record. A felony DUI cannot be expunged. Because Idaho lacks a broad sealing remedy, the practical effect is that most DUI convictions remain on the criminal record indefinitely and continue to count as priors during the 10-year look-back period. A person who wants to clear or set aside a record should confirm eligibility with the court that handled the case.

What to do after a DUI arrest in Idaho

An Idaho DUI creates two separate matters: a criminal case in the magistrate court and an administrative license case at the Idaho Transportation Department. The deadlines are short, so a common first step is to request the administrative hearing within seven days of the notice of suspension, because missing that window generally means the suspension takes effect automatically. The criminal case proceeds on its own schedule from arraignment through resolution. General information cannot tell you how your case will come out, since the outcome depends on the facts, the evidence, and your record. Many people consult a licensed Idaho DUI attorney to understand the charge, the administrative deadline, and the options for both the criminal case and the license case. Keep the arrest paperwork, the notice of suspension, and any test results in a safe place.