Maryland Alcohol Limit: BAC Thresholds, Penalties, and Interlock

The Maryland alcohol limit for driving is 0.08% blood alcohol concentration, the point at which the state charges driving under the influence (DUI). A second, lower threshold at 0.07% supports the lesser charge of driving while impaired (DWI). Commercial drivers are held to 0.04%, and drivers under 21 must have no detectable alcohol at all. Both DUI and DWI are criminal offenses, and since October 2024 nearly every impaired-driving disposition in Maryland also requires an ignition interlock device.

The BAC Numbers That Matter

Maryland Transportation Code 21-902 sets two adult thresholds. At 0.08% or higher, impairment is presumed automatically and prosecutors do not need separate evidence that your driving was affected. Between 0.07% and just under 0.08%, the test result creates what the statute calls “prima facie evidence” of impairment. That presumption can be challenged, but the reading alone is enough to charge DWI.¹

Two groups face stricter limits:

Commercial drivers holding a CDL are limited to 0.04% under federal regulations. A first DUI triggers a minimum one-year CDL disqualification, and it applies even when the driver was in a personal vehicle at the time of the offense.²
Drivers under 21 must have no detectable alcohol in their blood. The restriction is imposed automatically on every license issued to someone under 21 and remains until their 21st birthday. Violating it is a criminal offense carrying up to two months in jail and a $500 fine, and the MVA can suspend or revoke the license. If an underage driver’s BAC reaches 0.08% or higher, adult DUI penalties apply on top of the underage violation.³

Chemical Testing and the Cost of Refusing

By driving on Maryland roads, you have already consented to a chemical test if an officer has lawful grounds to request one. That is what “implied consent” means under Transportation Code 16-205.1.⁴

Refusing the test is punished separately from any DUI or DWI charge, and the administrative consequences are often worse than failing:

First refusal: 270-day license suspension.
Second or subsequent refusal: two-year suspension.
Mandatory one-year participation in the ignition interlock program if you want driving privileges during the suspension.⁵

These MVA penalties apply regardless of whether the criminal case ends in conviction, and they can take effect before the criminal case is resolved. A test result of 0.08% or higher on a first offense produces a 180-day administrative suspension on its own; a reading of 0.15% or higher carries stiffer periods.⁴

First-Offense Criminal Penalties

Both DUI and DWI are misdemeanors, but the gap between them is real.

DUI (0.08% or higher): up to one year in jail and a fine up to $1,200. Twelve points are assessed on your driving record, which triggers automatic license revocation.
DWI (0.07% to under 0.08%): up to two months in jail and a fine up to $500. Eight points are assessed, which triggers a license suspension.

Statutory maximums come from Section 21-902; the point assessments come from the MVA.¹⁶

Penalties are enhanced when a passenger under 18 was in the vehicle at the time of the offense.¹

How Penalties Escalate With Repeat Offenses

Maryland counts both DUI and DWI convictions toward your prior-offense total, and the ceiling rises fast.

Second DUI: up to two years in jail, fine up to $2,400, 12 points.
Second DWI: up to one year in jail, fine up to $500, 8 points.
Third offense (any combination of DUI or DWI): up to five years in jail and a fine up to $5,000.
Fourth or subsequent offense: penalties increase further beyond the third-offense maximums.

All tiers come from Section 21-902.¹ Courts treat repeat offenses with particular severity when prior convictions fell within the preceding five years, and judges frequently attach alcohol treatment, community service, and extended probation to repeat sentences.⁷

The Ignition Interlock Requirement

As of October 1, 2024, the interlock program covers virtually every impaired-driving outcome in Maryland, including DUI convictions, DWI convictions, and cases resolved through probation before judgment. There is no longer a disposition path that avoids it.⁵

The device requires a clean breath sample before the car will start and periodically while driving. How long you stay in the program depends on the offense:

BAC 0.08% to under 0.15%: 180 days.
BAC 0.15% or higher: one year.
Test refusal: one year.

Failed samples, missed calibration appointments, and tampering each extend participation by 30 days.⁵ The device itself typically costs $50 to $120 per month to lease and monitor, on top of installation and removal fees.

Points, Suspension, and Getting Your License Back

License consequences run on two tracks at once. The MVA acts on your test result administratively, while the criminal court can impose its own restrictions at sentencing.

On the points side, 8 to 11 points accumulated within two years produces a suspension; 12 or more produces a revocation. A DUI conviction adds 12 points by itself, and a DWI conviction adds 8.⁶

Reinstatement is not automatic once the suspension or revocation period ends. You will pay a $150 reinstatement fee to the MVA for any drug or alcohol-related suspension, complete any required interlock participation, and provide proof of insurance before driving privileges return.⁸

When a DUI Becomes a Much More Serious Charge

Two situations push impaired driving well past the standard penalty scheme.

Life-threatening injury caused by impaired driving is charged under Criminal Law 3-211. It remains a misdemeanor, but a first offense carries up to three years in prison and a $5,000 fine. With a prior impaired-driving conviction, that rises to five years and $10,000.⁹

When impaired driving causes a death, Maryland’s vehicular manslaughter while intoxicated statute carries up to 15 years in prison and fines up to $15,000 for a first offense. A driver with a prior DUI who kills someone faces up to 20 years and $20,000.

Underage Drinking Charges Beyond the Wheel

Separate from any driving offense, a minor caught possessing or consuming alcohol faces misdemeanor charges and a fine up to $500 for a first offense under Criminal Law 10-114, with increased penalties for repeat violations.¹⁰ Adults who knowingly allow underage individuals to possess or consume alcohol at a residence face charges under Criminal Law 10-117.¹¹

The zero-tolerance threshold for underage drivers reflects a federal mandate. The National Highway System Designation Act of 1995 required all states to adopt a maximum BAC of 0.02% for drivers under 21 or lose a portion of federal highway funds. That number is effectively the lowest level testing equipment can reliably detect.¹²

What a Conviction Actually Costs

Court-imposed fines are a fraction of the real bill. Maryland requires an SR-22 high-risk insurance filing for three years after a DUI conviction, during which annual premiums commonly double or triple. Over three years, the additional insurance cost alone can exceed the fines and legal fees combined.

Interlock costs run $50 to $120 per month for the lease and monitoring, plus one-time installation and removal fees. A 180-day program — the minimum for a first DUI under 0.15% — comes to roughly $300 to $720 in monthly fees before add-ons. The MVA charges $150 to reinstate.⁸

None of these costs are tax-deductible. The IRS does not allow deductions for fines or penalties paid for violating the law, and legal fees for defending against personal criminal charges are likewise not deductible.¹³

1
Maryland General Assembly. Maryland Transportation Code 21-902
2
Federal Motor Carrier Safety Administration. Disqualification of Drivers (383.51)
3
Maryland General Assembly. Maryland Transportation Code Section 16-113 – Restricted Licenses
4
Maryland General Assembly. Maryland Transportation Code Section 16-205.1
5
Maryland MVA. Ignition Interlock Program
6
Maryland MVA. Maryland Impaired Driving Laws
7
Maryland Courts. Maryland DWI and DUI Penalties
8
Maryland MVA. MVA Fee Listing
9
Maryland General Assembly. Maryland Criminal Law Code Section 3-211
10
Maryland General Assembly. Maryland Criminal Law Code Section 10-114
11
Maryland General Assembly. Maryland Criminal Law Code 10-117
12
GovInfo. Final Rule Implementing a New Program Enacted by the National Highway System Designation (NHS) Act of 1995
13
Internal Revenue Service. Publication 529, Miscellaneous Deductions