New Hampshire Ignition Interlock Requirements (2026): Costs & Authorized Providers
New Hampshire doesn’t mandate an ignition interlock for every DWI — a simple first offense may not trigger it. But Aggravated DWI (BAC 0.16% or higher, or a passenger under 16) always does, as does any second or subsequent conviction. Hardship cases can get up to 75% of installation and service costs covered through the providers’ required reserve funds. Here’s who needs one and how the program works.
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New Hampshire DWI interlock requirements at a glance
| Offense terms | DWI (Driving While Intoxicated) — standard. Aggravated DWI (265-A:3) — BAC 0.16%+, passenger under 16, racing, or refused with prior revocation in 10 years |
| All-offender? | No — simple first DWI has no statutory mandate; court or DMV may order it. Mandatory only for Aggravated DWI (1st or subsequent) and all 2nd+ convictions. |
| Simple 1st DWI — IID | No statutory mandate; court or DMV may order 12 months–2 years at their discretion. Required if taking the RSA 263:57-b limited license. |
| Aggravated 1st DWI — IID | Mandatory — 12 months to 2 years after the 18-month minimum revocation period (RSA 265-A:36, I) |
| 2nd DWI — IID | Mandatory — 12 months to 2 years, beginning after the 3-year revocation period |
| 3rd+ DWI — IID | Mandatory — 12 months to 2 years after the revocation period; 3rd-offense revocation is indefinite with a 5-year minimum before petitioning |
| Passenger under 16 | Aggravated DWI charge (265-A:3) — triggers mandatory IID regardless of BAC |
| Hardship cost relief | Up to 75% of installation and service costs covered from provider’s required reserve fund (Saf-C 6506.02; RSA 265-A:36, VI). Request at a DMV hearing on ability to pay, using form DSSP 358. |
| Removal process | Request removal from DMV; certificate issued within 5 business days if order has expired and no hearings are pending (Saf-C 6511.02) |
| Violation — within 120 days of removal request | More than one violation in the 120 days before removal = +120 days; other violations extend 30–120 days (Saf-C 6511.02(d), 6512.05) |
| SR-22 required? | Yes — after any DWI, leaving the scene, or 2nd+ reckless operation; 3 years from conviction or eligibility for restoration |
| Who administers | NH DMV — Ignition Interlock Program |
| Governing law | RSA 265-A:36; 265-A:36-a; 265-A:3; 265-A:18; 263:57-b; Saf-C 6500 |
Who needs an interlock in New Hampshire?
The IID requirement depends on whether your charge is a simple DWI or an Aggravated DWI:
- Simple first DWI (BAC 0.08–0.15%): No statutory mandate. However, the court or DMV may still order an IID, and it is required if you take the RSA 263:57-b limited license during your suspension. Confirm with your attorney whether your court or county typically orders one.
- Aggravated first DWI: Mandatory. This applies if your BAC was 0.16%+, you had a passenger under 16, you were racing, or you refused the test having had a prior revocation within 10 years. The IID period is 12 months to 2 years, beginning after the 18-month minimum revocation.
- Second or subsequent DWI: Mandatory regardless of BAC, with the IID period beginning after your revocation ends.
Hardship relief: up to 75% of costs covered through your provider. New Hampshire law (RSA 265-A:36, VI; Saf-C 6506.02) requires each authorized provider to maintain a reserve fund to cover up to 75% of installation and service costs for clients who demonstrate financial hardship. To access this relief: request a DMV hearing on ability to pay and submit financial affidavit form DSSP 358. There’s no published income threshold in the rule — the DMV makes the determination. If cost is a concern, request the hearing before installation.
NH DMV-authorized providers
Official provider list not publicly available. NH DMV states that five vendors are authorized but does not publish their names on its public-facing pages, and the official list was not reachable during our research. The providers below are inferred from vendor-operated NH location pages — they appear to serve New Hampshire but their authorization status is based on their own marketing, not a verified DMV list. Before signing with any provider, call NH DMV directly at (603) 227-4000 or check dmv.nh.gov to confirm current authorization.
| Provider (authorization unverified — confirm with DMV) | Monthly est. | |
|---|---|---|
| Intoxalock | $60–100 | 888-283-5899 |
| Smart Start | $70–100 | 800-831-3299 |
| LifeSafer | $65–95 | 800-634-3077 |
| RoadGuard (Dräger) | $65–95 | 833-545-0368 |
Confirm authorization with NH DMV before signing — call (603) 227-4000 or visit dmv.nh.gov. DMV lists five authorized vendors but does not publish their names. The providers above are inferred from location pages only. If financial hardship applies, contact DMV about the 75% cost-relief program before installation.
What an interlock costs in New Hampshire
| Installation (one time) | $70–150 (up to 75% covered for hardship cases) |
| Monthly lease + monitoring | $60–100 (up to 75% covered for hardship cases) |
| Removal | $50–75 |
| State IID program fee | None identified |
Over a 12-month Aggravated DWI first-offense IID term, expect roughly $900–1,400 (or as low as $225–350 with full 75% hardship relief). Estimate your exact cost →
How to get installed — 5 steps
- Confirm with your attorney whether an IID is required in your case — mandatory for Aggravated DWI and all 2nd+ convictions; discretionary for a simple first DWI.
- If cost is a concern, call NH DMV at (603) 227-4000 to request a hearing on ability to pay before contacting a provider. Bring financial affidavit form DSSP 358 to the hearing to request the up-to-75% hardship relief.
- Call NH DMV to confirm which five vendors are currently authorized. Contact one of them and schedule installation — your IID term doesn’t begin until the device is installed and DMV records the order.
- Serve the full IID term. Keep every calibration appointment. For removal eligibility, you need no more than one violation in the 120 days before you request removal.
- Request removal from DMV after your order expires and no hearings are pending. DMV issues a certificate of removal within 5 business days.
Aggravated DWI or 2nd offense? Call DMV to confirm the authorized vendors, then book installation.
Book installation
Violations — the 120-day window before removal
New Hampshire’s violation rules under Saf-C 6511.02(d) and 6512.05 focus on the period before you request removal:
- More than one violation in the 120 days before a removal request: +120 days added to your term
- Other violations during the term: 30–120 days added per occurrence depending on type
To remove cleanly, you need no more than one violation in the 120 consecutive days before your removal request. Keep an especially clean record in the final four months of your term.
SR-22 insurance is required after any DWI in New Hampshire. 3 years from conviction or restoration eligibility. See New Hampshire SR-22 costs and cheapest carriers →
New Hampshire DWI interlock FAQ
Is an interlock mandatory for a first DWI in New Hampshire?
Only if it’s an Aggravated DWI — BAC 0.16%+, a passenger under 16, racing, or a refusal with a prior revocation within 10 years. A simple first DWI (BAC 0.08–0.15%) has no statutory IID mandate, though the court or DMV may still order one. If you’re taking the RSA 263:57-b limited license during your suspension, the IID is also required. Confirm with your attorney for your specific situation.
What is an Aggravated DWI in New Hampshire?
An Aggravated DWI (RSA 265-A:3) is charged when a DWI involves any of these aggravating factors: BAC of 0.16% or higher at the time of driving; a passenger under 16 years old in the vehicle; racing on a way; or refusal of a chemical test having had a prior license revocation within the previous 10 years. An Aggravated DWI conviction always triggers the mandatory IID requirement.
How can I get cost relief for the interlock in New Hampshire?
New Hampshire law (RSA 265-A:36, VI; Saf-C 6506.02) requires each authorized vendor to maintain a reserve fund covering up to 75% of installation and service costs for financial hardship cases. To access it: request a DMV hearing on ability to pay before installation and submit financial affidavit form DSSP 358. There’s no published income threshold — DMV makes the determination. Act before installation, not after.
Which providers are authorized in New Hampshire?
NH DMV states that five vendors are authorized but does not publish their names publicly. The providers listed on this page are inferred from vendor location pages only — authorization has not been verified against the official DMV list. Call NH DMV at (603) 227-4000 to get the current authorized vendor list before signing with anyone.
How does the 120-day removal window work?
Under Saf-C 6511.02(d), if you have more than one violation in the 120 days immediately before you request removal, 120 additional days are added to your term. Other violations during the term add 30–120 days. To remove cleanly, you need no more than one violation in the final 120 consecutive days. DMV issues the removal certificate within 5 business days if the order has expired and no hearings are pending.
Sources:
NH DMV — Ignition Interlock Program;
RSA 265-A:36; 265-A:36-a; 265-A:3; Saf-C 6506.02; 6511.02; 6512.05.
Last verified August 2026.
Advertising disclosure: We may be compensated when you contact a provider through our numbers or links. This doesn’t affect our rankings or information. Provider authorization status is unverified — confirm with NH DMV before signing. Content is informational only — not legal advice.