A Complete Guide to New Hampshire DUI/DWI Laws: From First Offense to Felony Charges

June 20, 2025

A Complete Guide to New Hampshire DUI/DWI Laws: From First Offense to Felony Charges

Introduction

New Hampshire, known for its "Live Free or Die" motto, has strict laws against impaired driving, officially termed "Driving While Intoxicated" (DWI). These regulations are rigorously enforced through both criminal penalties imposed by the courts and administrative actions by the New Hampshire Department of Safety (DOS). The state aims to deter individuals from operating vehicles while affected by alcohol or drugs, thereby enhancing public safety on its roads. Penalties for DWI in New Hampshire are significant, escalating considerably for repeat offenses, higher Blood Alcohol Concentration (BAC) levels, or those involving aggravating circumstances such as serious injury or child endangerment. Understanding these laws is crucial for anyone driving in New Hampshire.

The General Framework of New Hampshire DWI Laws

In New Hampshire, a person commits the offense of DWI if they are driving, operating, or in actual physical control of a vehicle, OHRV (Off-Highway Recreational Vehicle), or boat upon any way while:

Under the influence of intoxicating liquor or any drug to a degree that impairs their driving ability. OR
Having a Blood Alcohol Concentration (BAC) of $0.08%$ or more (this is a "per se" violation, meaning no other evidence of impairment is needed).
For commercial vehicle operators: Having a BAC of $0.04%$ or more.
For drivers under 21 (Zero Tolerance Law): Having a BAC of $0.02%$ or more.

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Even if your BAC is below the specific "per se" limits, you can still face DWI charges if law enforcement can prove that your driving ability was "impaired" by alcohol or drugs based on observations, field sobriety tests, or other evidence.

Implied Consent Law

New Hampshire has a robust implied consent law (RSA 265-A:4). By driving or operating a vehicle on New Hampshire roads, you are legally deemed to have given your consent to a chemical test (blood, breath, or urine) to determine the concentration of alcohol or the presence of drugs in your system if a law enforcement officer has reasonable grounds to suspect impairment and lawfully arrests you for DWI.

Refusal to Test: Refusing to submit to a chemical test after a lawful arrest for DWI in New Hampshire carries immediate and severe administrative penalties from the Department of Safety (DOS), separate from any criminal prosecution. Your refusal can also be used as evidence against you in court.

First refusal with no prior DWI convictions: Automatic 180-day driver's license suspension.
First refusal with prior DWI conviction or prior refusal: Automatic 2-year driver's license suspension.

These administrative suspensions take effect upon notice from the DOS and run consecutively to any court-imposed suspension if you are convicted of DWI. You are entitled to an administrative hearing to challenge the suspension, which must be requested promptly (typically within 30 days of receiving the suspension notice).

New Hampshire DWI Statistics

Impaired driving remains a significant public safety concern in New Hampshire. According to the New Hampshire Office of Highway Safety (OHS) and other sources:

In 2023, New Hampshire saw a 30% increase in law enforcement agency participation in highway safety grant programs, leading to increased visibility and enforcement, including DUI saturation efforts.
Preliminary data for 2024 indicates a 60% increase in law enforcement participation compared to 2022, suggesting continued ramped-up enforcement activities.
In 2022, 36% of New Hampshire traffic deaths were related to alcohol-impaired driving. Historically, about one-third of the state's traffic fatalities involve impaired driving.
While overall fatalities decreased by 11% in 2023 compared to 2022, impairment, speeding, and distracted driving remain top contributing factors to crashes.
In 2021, 10.7% of all arrests in New Hampshire were for DWI, totaling 4,067 arrests.

These statistics highlight the ongoing challenge of impaired driving and the state's proactive measures to address it.

Penalties for DWI in New Hampshire

New Hampshire's DWI penalties are substantial and become significantly more severe with each subsequent conviction. New Hampshire uses a 10-year "look-back" period for determining if a DWI is a second or third offense. For a fourth or subsequent offense, it typically becomes a felony, counting all prior convictions.

First Offense DWI (Class B Misdemeanor)

For a first-time DWI conviction in New Hampshire (no prior convictions within the last 10 years):

Jail Time: No mandatory jail time, but up to 6 months is possible.
Fines: $500 to $1,200, plus a 24% penalty assessment.
License Revocation: 9 months to 2 years.
- Reduction: The revocation period can be reduced to 90 days if the driver enters into the First Offender Impaired Driver Intervention Program (IDIP) within 45 days of conviction and completes it prior to reinstatement.
Impaired Driver Intervention Program (IDIP): Mandatory completion (minimum 20 hours) prior to license reinstatement.
Substance Abuse Screening/Evaluation: Mandatory within 14 days of conviction, with adherence to any recommended treatment.
SR-22 Insurance: Mandatory proof of financial responsibility for 3 years.
Ignition Interlock Device (IID): May be ordered by the court, or by the Department of Safety at a separate hearing, as a condition of license restoration, especially if a probationary license is sought.

Aggravated DWI (Class A Misdemeanor or Felony)

An Aggravated DWI is charged if, in addition to DWI, one of the following factors is present:

BAC of $0.16%$ or higher.
Driving at a speed 30 mph over the prima facie limit.
Causing a collision resulting in serious bodily injury.
Attempting to elude law enforcement.
Carrying a passenger under the age of 16.
Jail Time: Mandatory minimum 10 consecutive days (with 3 consecutive 24-hour periods served in the county house of corrections, and 7 days potentially served in a residential program like the Multiple Offender Program (MOP) or under home confinement). Up to 1 year is possible.
- Note: If the aggravating factor is causing serious bodily injury, it can be a Class B felony, carrying prison time.
Fines: $750 to $2,000, plus a 24% penalty assessment.
License Revocation: 18 months to 2 years (6 months may be suspended upon entry into a relevant program).
Treatment: Mandatory intensive treatment program.
IID: Mandatory installation upon license restoration.

Second Offense DWI (within 10 years)

If prior conviction within 2 years:
- Jail Time: Mandatory minimum 30 consecutive days in the county house of corrections (no reduction for good behavior). Up to 1 year is possible.
- Fines: $750 to $2,000, plus a 24% penalty assessment.
- License Revocation: 3 years.
- Multiple Offender Program (MOP): Mandatory completion of an approved residential or intensive outpatient program.
- IID: Mandatory installation.
If prior conviction between 2 and 10 years:
- Jail Time: Mandatory minimum 3 consecutive days in the county house of corrections (up to 1 year possible).
- Fines: $750 to $2,000, plus a 24% penalty assessment.
- License Revocation: 3 years.
- Multiple Offender Program (MOP): Mandatory completion.
- IID: Mandatory installation.

Third Offense DWI (within 10 years - Class A Misdemeanor)

Jail Time: Mandatory minimum 180 consecutive days (30 days served in the county house of corrections, with the remainder potentially deferred or served in a residential treatment program). Up to 1 year is possible.
Fines: $750 to $2,000, plus a 24% penalty assessment.
License Revocation: Indefinite, with no possibility of reinstatement for at least 5 years from the date of conviction.
Treatment: Mandatory completion of a residential inpatient program (at driver's expense).
IID: Mandatory installation for a specified period if license is ever reinstated.
Vehicle Forfeiture: Possible.

Fourth and Subsequent Offense DWI (Felony - Class B Felony)

This applies to a fourth or subsequent conviction, regardless of when prior offenses occurred (lifetime look-back for felony classification).

Prison Time: Mandatory minimum 1 to 7 years in state prison (or 3 1/2 to 7 years). At least 180 days must be served consecutively.
Fines: $750 to $2,000.
License Revocation: Indefinite, with no possibility of reinstatement for at least 7 years from the date of conviction.
Treatment: Mandatory completion of an approved residential treatment program.
IID: Mandatory installation for a specified period if license is ever reinstated.
Felony Criminal Record: Permanent felony conviction with severe lifelong implications.

Other Significant Penalties:

DWI Causing Serious Bodily Injury (Class B Felony): If the DWI causes serious bodily injury to another person, it is a Class B felony, punishable by up to 7 years in state prison and a fine of up to $4,000.
Negligent Homicide (Class A Felony): If the DWI causes the death of another person, it is a Class A felony, punishable by up to 15 years in state prison and a fine of up to $4,000. More severe cases (e.g., Manslaughter) can carry 15 to 30 years.
Under 21 DWI (BAC $0.02%$ to $0.08%$ ):
- First offense: 20 to 90-day additional license loss (on top of any court-imposed suspension), fine.
- Repeat offenses lead to longer suspensions and more intensive treatment.
Driving While Suspended/Revoked for DWI: This is a separate criminal offense with significant penalties, including mandatory jail time.
Collateral Consequences: A DWI conviction can lead to social stigma, difficulty with employment, professional license issues, increased insurance rates (SR-22 requirement), issues with renting vehicles, and restrictions on travel (e.g., entry into Canada).

Conclusion

New Hampshire's DWI laws are rigorous, featuring substantial penalties that escalate rapidly for repeat offenses, especially those occurring within a short timeframe. The combination of mandatory jail sentences (for repeat or aggravated offenses), significant fines, lengthy and often indefinite license revocations (with the requirement for Ignition Interlock Devices), and comprehensive substance abuse programs underscores the state's serious approach to impaired driving. The strict implied consent law and the impact of aggravating factors further enhance the severity of consequences. Understanding the nuances of these laws, including the specific look-back periods and the dual nature of administrative and criminal penalties, is paramount for any driver in New Hampshire. For anyone facing a DWI charge in the Granite State, immediate consultation with an experienced New Hampshire DWI defense attorney is strongly advised to navigate the complexities of the legal system and safeguard your rights and future.

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