In Wisconsin, a restricted controlled substance is a short, statutory list of drugs that makes driving illegal the moment any detectable amount shows up in your blood. The list, defined in Wis. Stat. § 340.01(50m), covers Schedule I drugs (other than THC), the heroin metabolite 6-monoacetylmorphine, Schedule I analogs, cocaine and its metabolites, methamphetamine, and Delta-9-THC at a concentration of 1 nanogram per milliliter or higher.1Wisconsin State Legislature. Wisconsin Statutes 340.01 – Words and Phrases Defined If one of these turns up in a blood test taken after a traffic stop, the state does not have to prove you were impaired. The test result is the offense.
Why the Category Exists
Wisconsin treats these drugs differently from the broader universe of controlled substances. A standard operating-while-intoxicated case built on drugs requires the prosecution to show your ability to drive was actually affected. A restricted controlled substance case does not. The legislature decided that for this narrow list, presence in the bloodstream is enough, which sidesteps the hard science of proving impairment from drugs that affect people differently depending on tolerance, timing, and metabolism.
The practical effect for a driver is blunt. Arguments about how you felt, how long ago you used, or how well you performed field sobriety tests do very little against a positive blood result.
The Substances on the List
The statute names six categories:
- Schedule I controlled substances other than tetrahydrocannabinols. This captures heroin, LSD, MDMA, psilocybin, and many others.
- 6-monoacetylmorphine, the specific compound your body produces when breaking down heroin.
- Controlled substance analogs of Schedule I drugs, which reaches designer compounds that have not yet been individually scheduled.
- Cocaine or any of its metabolites. The metabolite benzoylecgonine can remain detectable in blood for days after use.
- Methamphetamine.
- Delta-9-THC at 1 nanogram per milliliter of blood or higher.
The THC rule is the one that most often surprises people. Only active Delta-9-THC counts, and only at 1 ng/mL or above. Non-psychoactive metabolites like carboxy-THC, which can linger in blood for weeks, are explicitly excluded.1Wisconsin State Legislature. Wisconsin Statutes 340.01 – Words and Phrases Defined That threshold is still low. Regular users can exceed it hours or even a day after last consuming marijuana. For cocaine, by contrast, any amount of the drug or its metabolites satisfies the standard.
What a Positive Test Means for the Driver
Wis. Stat. § 346.63(1)(am) makes it illegal to drive with a detectable amount of a restricted controlled substance in your blood.2Wisconsin State Legislature. Wisconsin Statutes 346.63 – Operating Under Influence of Intoxicant or Other Drug It is a per se violation. The blood result alone establishes the offense; the prosecution does not need to show weaving, slurred speech, or failed field sobriety tests.
When an officer suspects drug impairment, the standard procedure is a blood draw at a medical facility. Wisconsin’s implied consent law treats every licensed driver as having already agreed to chemical testing. The sample is analyzed at the State Laboratory of Hygiene or a certified private lab for the specific compounds in the restricted substance definition.3Wisconsin Court System. Wis JI-Criminal 2664B – Operating a Motor Vehicle With a Detectable Amount of a Restricted Controlled Substance
A defense attorney can attack the stop, the blood draw procedure, chain of custody, or the lab analysis. What rarely works is arguing that you felt capable of driving. The law is built on chemistry.
The Valid Prescription Defense
Wisconsin recognizes an affirmative defense for three of these substances: methamphetamine, gamma-hydroxybutyric acid (GHB), and Delta-9-THC. If you held a valid prescription at the time of driving, you can raise it as a defense to the per se charge, and the burden is on you to prove the prescription was valid by a preponderance of the evidence.4Wisconsin State Legislature. Wisconsin Code 346.63 – Operating Under Influence of Intoxicant or Other Drug
The defense is narrower than it sounds. There is no prescription defense for cocaine or heroin. And even with a valid prescription, if your driving was actually impaired by the medication, the state can still charge you under the general impairment-based OWI statute, § 346.63(1)(a), which only requires proof that you were too impaired to drive safely.
The CBD and Legal Hemp Trap
Hemp with no more than 0.3 percent Delta-9-THC on a dry weight basis is legal in Wisconsin, and CBD products derived from compliant hemp are lawful to buy and use.5Wisconsin State Legislature. Change to Federal Definition of Hemp The driving statute contains no carve-out for THC that entered your blood through a legal product. If a CBD oil, edible, or tincture pushes your Delta-9-THC level to 1 ng/mL or higher, you are driving with a restricted controlled substance under Wisconsin law.
Many commercial CBD products contain trace Delta-9-THC, and at higher doses the trace can become a measurable blood level. Legality at the point of purchase is not a defense at the point of the traffic stop. The prescription defense covers prescription Delta-9-THC products such as dronabinol, not over-the-counter CBD.
Penalties by Offense Number
Penalties escalate with each OWI-related conviction, and Wisconsin counts prior alcohol and drug offenses together, not separately.
- First offense: civil forfeiture of $150 to $300, plus a $535 OWI surcharge. No criminal conviction. License revoked six to nine months.
- Second offense (with a prior OWI within 10 years): misdemeanor, $350 to $1,100 fine plus the surcharge, and five days to six months in jail.
- Third offense: $600 to $2,000 fine plus the surcharge, and 45 days to one year in county jail.
- Fourth offense: Class H felony, minimum $600 fine plus the surcharge, and 60 days to six years in prison.
The fourth-offense cliff is the one that reshapes a life. A fourth OWI is a felony no matter how long ago the earlier convictions occurred, because the counting window for a fourth or later offense is lifetime rather than the 10-year window used at the second-offense stage.6Wisconsin State Legislature. Wisconsin Code 346.65 – Penalty for Violating Sections 346.62 to 346.64 The $535 surcharge applies at every tier on top of the base fine.7Wisconsin State Legislature. Wisconsin Code 346.655 – Driver Improvement Surcharge Court costs and Chapter 814 fees push the real total higher than the base fine suggests.
License Revocation and Driving During Revocation
A conviction triggers a mandatory license revocation. The length depends on your record:
- First offense: 6 to 9 months. You can apply for an occupational license immediately.
- Second offense: 1 year to 18 months. You must wait 45 days, complete your Intoxicated Driver Program assessment, and be in compliance with your driver safety plan before an occupational license is available.
- Third and later offenses: 2 to 3 years, with the same 45-day wait, assessment, and plan-compliance requirements.
All revocation periods double if a passenger under 16 was in the vehicle.8Wisconsin Department of Transportation. Driver License Withdrawals
An occupational license lets you drive during limited hours for work, school, or medical appointments. To qualify you must file an SR-22 certificate of financial responsibility covering every vehicle you want to operate.9Wisconsin State Legislature. Wisconsin Statutes 343.10 – Occupational Licenses For second and later offenses, the court must order an ignition interlock device, and no occupational license issues until you pay the interlock surcharge and show the device is installed.
Ignition Interlock and SR-22
An ignition interlock device is required on all your vehicles if you have any prior OWI-related conviction, suspension, or revocation; if your blood alcohol concentration was 0.15 or higher on a first offense; or if you refused the chemical test.10Wisconsin State Legislature. Wisconsin Code 343.301 – Installation of Ignition Interlock Device For a first-offense restricted substance case with no prior history and no refusal, interlock does not automatically apply.
If outfitting every vehicle would cause genuine financial hardship, the court can exempt one or more. Households at or below 150 percent of the federal poverty line have their share of installation and maintenance capped at half.
The SR-22 is a separate requirement. It must stay active for three years from the date you become eligible to reinstate. A first-offense OWI where revocation is the only consequence is the one common situation that does not require SR-22.11Wisconsin Department of Transportation. SR22 Certificate – Proof of Insurance/Financial Responsibility
Mandatory Alcohol and Drug Assessment
Every OWI conviction, including a restricted substance case, requires you to contact an approved Intoxicated Driver Program assessment facility within 72 hours of the conviction. The assessment evaluates your relationship with alcohol and drugs and places you in a driver safety plan category, which determines the treatment or education you must complete.12Wisconsin Department of Transportation. OWI Assessment and Driver Safety Plan
Plans range from an educational program for an irresponsible user to intensive inpatient treatment for someone assessed as chemically dependent. You have one year from the assessment date to finish the plan, with a single four-month extension available if you request it in advance. Missing appointments, failing to pay program fees, or picking up a new OWI during the program counts as non-compliance and leads to license cancellation or denial.
Refusing the Blood Test
Refusing a chemical test after a lawful arrest is treated as its own violation on top of any OWI case:
- First refusal: one-year revocation, occupational license eligibility after 30 days.
- Second refusal (or one prior OWI-type offense within 10 years): two-year revocation, occupational license after 90 days.
- Third or later refusal: three-year revocation, occupational license after 120 days.
These periods double if a child under 16 was in the vehicle, and a refusal triggers the interlock requirement.13Wisconsin State Legislature. Wisconsin Statutes 343.305 – Tests for Intoxication; Administrative Suspension and Court-Ordered Revocation Refusal does not stop the OWI prosecution. Officers can get a warrant for a blood draw, and the refusal itself is admissible against you at trial.
If You Hold a CDL
A commercial driver’s license carries its own penalty track. A first OWI-related offense disqualifies the CDL for one year. A second results in lifetime disqualification from commercial driving.14Wisconsin State Legislature. Wisconsin Code 343.315 – Commercial Motor Vehicle Disqualification These disqualifications apply to OWI offenses in any vehicle, not just offenses committed in a commercial one. For a CDL holder, a single restricted substance violation can end a career built on the credential.