Iowa OWI Laws Explained

By Javier Marín, Editor·Last reviewed September 2026·How we check this

Iowa's impaired-driving statute is Iowa Code §321J.2 — Operating While Intoxicated (OWI). The "OWI" terminology is distinct from the more common "DUI" used in many states; Iowa adopted the operating-while-intoxicated framing decades ago. An OWI arrest triggers two parallel processes — a criminal case in district court, and an administrative implied-consent action by Iowa DOT — each with separate timelines and consequences.

The legal threshold

Iowa's per-se OWI thresholds:

Adults 21+: 0.08% BAC.
Aggravated: 0.15% BAC or higher (enhanced penalties).
Drivers under 21: 0.02% BAC (Iowa's school-age limit, separate administrative consequence).
Commercial drivers (CDL): 0.04% BAC.
Drugs: any controlled substance impairing driving — Iowa does not use a per-se THC threshold but uses impairment evidence and chemical-test results.

Iowa also charges OWI on impairment evidence below 0.08% under Iowa Code §321J.2(1)(a), the "under the influence" subsection. Officers rely on field sobriety tests, drug-recognition expert (DRE) evaluations, and observed driving patterns to support those charges.

Implied consent and chemical testing

Iowa's implied-consent law presumes any driver on Iowa roads has consented to chemical testing if arrested for OWI. Refusing the breath, blood, or urine test triggers an automatic license revocation regardless of the criminal outcome. After arrest, the driver receives a notice of revocation and has 10 days to request an administrative hearing with Iowa DOT to challenge the action.

Implied-consent revocations:

1-year revocation for a first refusal.
2-year revocation for a refusal with a prior OWI or refusal in the past 12 years.

Revocations for failed tests

If the chemical test result is 0.08% or higher (0.04% CDL, any measurable amount under 21):

180-day revocation for a first failure.
1-year revocation for a second failure within 12 years.
6-year revocation for a third failure within 12 years.

The administrative revocation runs in parallel with any criminal license action. Drivers can request an administrative hearing within 10 days to challenge whether the stop was lawful, whether the test was properly administered, and whether the BAC reading is reliable.

First-offense criminal penalties

A first-offense OWI in Iowa is a serious misdemeanor, carrying:

Mandatory minimum 48 hours in jail (judge can impose up to 1 year).
Fine of $1,250 minimum (range $625-$1,250 base, with surcharges adding 15-30%).
180-day administrative license revocation.
Mandatory completion of a substance-abuse evaluation by an approved provider.
Treatment or course of treatment recommended by the evaluation.
Drinking-driver course (a state-approved education class).
Ignition interlock device (IID) for at least 1 year on any vehicle the driver operates after reinstatement.
SR-22 financial responsibility filing for 2 years — see Iowa car insurance.

Deferred judgment

Iowa allows eligible first-offense OWI defendants to seek a deferred judgment under Iowa Code §907.3. Under deferred judgment, the defendant enters a guilty plea, the court defers imposition of conviction, and the defendant completes a probation period with conditions. If probation is completed successfully, the OWI charge is dismissed and no conviction appears on the criminal record. The administrative license revocation by Iowa DOT still applies.

Eligibility limits: no prior OWI conviction, no prior deferred judgment within the lookback window, no aggravated OWI (BAC 0.15%+), no OWI involving injury or death, and no commercial driver's license at the time of the offense. The deferred-judgment application must be filed before sentencing.

Aggravated OWI (0.15% and above)

BAC of 0.15% or higher upgrades to aggravated OWI with enhanced penalties:

Minimum 7 days mandatory jail time on a first offense.
Higher fines.
Longer license revocation.
Longer mandatory IID period.
Vehicle impoundment in some circumstances.

Repeat offenses

A second OWI within 12 years is an aggravated misdemeanor:

Mandatory minimum 7 days in jail (judge can impose up to 2 years).
Fine $1,875-$6,250.
1-year license revocation.
Mandatory IID for at least 1 year.

A third OWI within 12 years is a Class D felony — up to 5 years in prison, $9,375 fine, and 6-year license revocation. Iowa's lookback for enhancement purposes is 12 years for most provisions; OWI convictions never roll off the criminal record.

Underage zero-tolerance

Drivers under 21 with a BAC of 0.02% or higher face an automatic license suspension (60 days for a first offense, 90 days for a second). These are administrative actions handled separately from any criminal OWI charge — see Iowa intermediate license.

For the path back to driving after an OWI revocation, see the Iowa suspended license page. For broader context on national DUI law, see the comparison guide.