What Is The Zero Tolerance Law? Underage DUI Penalties

Zero tolerance laws make it illegal for drivers under 21 to operate a vehicle with any measurable amount of alcohol in their system—typically a blood alcohol content (BAC) of 0.01% or 0.02%.

While drivers 21 and over face DUI charges at 0.08% BAC, underage drivers get hit with zero tolerance violations for having essentially any alcohol detectable in their blood.

Here’s the truth: One beer at a party can cost an 18-year-old their license for a year, even though they weren’t legally drunk.

How Zero Tolerance Laws Work

Zero-tolerance laws set a maximum BAC of less than 0.02 g/dL for drivers under 21 years old, and violators have their driver’s licenses suspended or revoked.

The core principle is simple: If you’re under 21, you’re not supposed to drink alcohol at all. Zero tolerance laws extend that prohibition to driving.

What triggers a violation:

Any detectable alcohol (0.01% BAC or higher in most states)
Refusing to take a preliminary breath test (PBT)
Having alcohol in your possession while driving

In 1995, zero tolerance passed into federal law, making it illegal for anyone under 21 to drive with any measurable amount of alcohol. By 1998, zero tolerance was passed in all 50 states.

As of January 2026, all 50 states maintain zero tolerance laws for underage drivers, though specific BAC thresholds and penalties vary.

Zero Tolerance BAC Limits by State

While the adult DUI limit is 0.08% nationwide (except Utah at 0.05%), zero tolerance limits for drivers under 21 vary:

Most common thresholds:

0.01% BAC: 16 states
0.02% BAC: 34 states and Puerto Rico
0.00% BAC: Some states for drivers under 18

The zero tolerance law applies to all drivers under the age of 21 and makes it illegal for an underage driver to have a blood alcohol content of over 0.01 percent.

What 0.01% BAC actually means: One standard drink can put you at 0.02% BAC, depending on your weight and metabolism. Even mouthwash, certain medications, or communion wine can trigger a positive reading.

Bottom line: If you’re under 21, don’t drive after consuming anything containing alcohol.

💡 Pro Tip
Many states allow officers to use preliminary breath test (PBT) devices at the roadside for zero tolerance enforcement. These tests happen before arrest, and refusal to take one results in automatic license suspension—often longer than if you’d failed the test.

Penalties for Zero Tolerance Violations

Zero tolerance violations are typically administrative offenses, not criminal charges—though you can face both.

First offense penalties (typical across states):

License suspension: 30 to 90 days minimum
Fines: $100 to $500
Alcohol education programs: 8 to 40 hours
Community service: 20 to 60 hours

Second offense penalties:

License suspension: 90 days to 1 year
Fines: $200 to $1,000
Extended alcohol education: 20+ hours
Possible restricted license ineligibility

Third offense penalties:

License revocation: 180 days to 2 years
Criminal charges: Misdemeanor in most states
Fines: $400 to $2,000
Potential jail time: Up to 6 months

In Texas, the consequences for a minor on the first offense of driving under the influence of alcohol include a Class C misdemeanor punishable by a fine up to $500 and 60 days driver’s license suspension.

What Is the Zero Tolerance Law Underage DUI Penalties

Additional consequences:

Insurance rate increases (often 50-200%)
SR-22 insurance requirement in some states
Employment difficulties (background checks)
College admission complications
Loss of scholarships

Understanding these penalties is as critical as knowing Is Your License Suspended Immediately After a DUI—because zero tolerance violations trigger administrative suspensions that start before any court hearing.

Zero Tolerance vs. Standard DUI Charges

You can face BOTH zero tolerance AND DUI charges simultaneously.

Zero Tolerance (Administrative):

BAC threshold: 0.01% or 0.02%
Handled by DMV/licensing authority
Penalties: License suspension, fines, education
No criminal record in most cases

DUI/DWI (Criminal):

BAC threshold: 0.08% (or impairment evidence)
Handled by criminal courts
Penalties: Criminal record, jail time, probation, higher fines
Long-term consequences more severe

Example: An underage driver with 0.05% BAC faces:

Administrative zero tolerance suspension (30-90 days)
Criminal DUI charges (because they’re impaired, even though under 0.08%)
Separate penalties for each violation

This dual prosecution means longer license suspensions, higher fines, and more severe long-term consequences than either violation alone.

Beyond Driving: Other Zero Tolerance Applications

While most people associate zero tolerance with underage DUI, the term applies to multiple legal contexts:

Drug-Impaired Driving: Zero tolerance laws make it illegal to drive with any measurable amount of specified drugs in the body, and 16 states have zero tolerance laws in effect for one or more drugs.

These laws prohibit driving with ANY detectable amount of illegal drugs (marijuana, cocaine, methamphetamine) regardless of impairment.

School Discipline: Zero tolerance policies mandate predetermined consequences (usually expulsion) for weapons, drugs, violence, or threats—regardless of circumstances.

Workplace Violations: Many employers maintain zero tolerance for drug use, sexual harassment, violence, or theft, meaning first violations result in immediate termination.

Firearms Violations: Federal zero tolerance applies to convicted felons possessing firearms—no exceptions, mandatory minimum sentences.

How to Fight a Zero Tolerance Violation

Challenging administrative suspension:

You typically have 10-30 days to request a DMV hearing after arrest.

Common defenses include:

Improper stop: Officer lacked reasonable suspicion
Faulty testing: PBT device wasn’t calibrated or maintained properly
Rising BAC: Alcohol absorbed after you stopped driving but before testing
Medical conditions: Diabetes, GERD, or other conditions causing false positives
Mouth alcohol: Recent use of mouthwash, breath spray, or medication

Procedural defenses:

Officer failed to read implied consent warnings
Testing violated proper procedure
Chain of custody problems with blood samples

An experienced DUI attorney can identify which defenses apply to your case and significantly improve your chances of beating the charge.

If you’re dealing with complications from How Many Times Can a DUI Case Be Postponed, the same attorney can help navigate continuances and delays.

What Parents and Underage Drivers Must Know

For parents:

Have the conversation early—before your teen gets a license
Explain zero tolerance clearly—any alcohol means license suspension
Set consequences at home—beyond legal penalties
Provide alternatives—ride-sharing apps, no-questions-asked pickup policy
Monitor behavior changes—secretiveness, smell of alcohol, late nights

For underage drivers:

Understand implied consent—by having a license, you’ve already agreed to testing
Know your rights—you can request an attorney before answering questions
Don’t refuse the breath test—refusal penalties are often harsher
Call a lawyer immediately—before making any statements
Request a DMV hearing—don’t accept automatic suspension without fighting

If you’re at a party:

Don’t drive after any alcohol consumption—period
Call a parent, rideshare, or friend
Stay overnight if necessary
Remember: underage drinking itself is illegal, but driving makes it infinitely worse

Recent Changes to Zero Tolerance Enforcement (2025-2026)

As of January 2026, several states have strengthened zero tolerance enforcement:

Enhanced penalties: Some states now mandate ignition interlock devices (IID) even for first-time zero tolerance violations if BAC exceeds 0.05%.

Extended administrative suspensions: California, Texas, and Florida increased minimum suspension periods for repeat offenses in late 2025.

Marijuana-specific provisions: Following marijuana legalization in additional states, zero tolerance now explicitly covers THC for underage drivers in 18 states as of Q4 2025.

Technology integration: More law enforcement agencies use portable PBT devices capable of detecting alcohol levels as low as 0.005%, making zero tolerance easier to enforce.

Important Legal Disclaimer

This article provides general information about zero tolerance laws as of January 2026. Zero tolerance penalties and procedures vary by state. AllAboutLawyer.com does not provide legal advice. If you’re facing zero tolerance or DUI charges, consult a qualified DUI defense attorney in your jurisdiction immediately.

For official information, visit the National Highway Traffic Safety Administration (NHTSA) or your state’s DMV website.

Facing underage DUI or zero tolerance charges? Getting experienced legal representation can make the difference between license suspension and keeping your driving privileges. Learn more at our DUI defense resource center.

Stay informed, stay protected. — AllAboutLawyer.com

Last Updated: January 29, 2026 — We keep this current with the latest legal developments

Sources:

National Highway Traffic Safety Administration (NHTSA) – Zero Tolerance Law Enforcement
Mothers Against Drunk Driving (MADD) – Zero Tolerance History
Governors Highway Safety Association – Drug-Impaired Driving Laws
California DMV – Zero Tolerance Administrative Suspension
Texas Department of Public Safety – Zero Tolerance Law

About the Author

Sarah Klein, JD, is a former criminal defense attorney with hands-on experience in cases involving DUIs, petty theft, assault, and false accusations. Through All About Lawyer, she now helps readers understand their legal rights, the criminal justice process, and how to protect themselves when facing charges.
Read more about Sarah