Four states cap what an interlock may cost. In most, nobody publishes a number
The device is the same federally specified box wherever you are. What you pay for it is not, and the reason is regulation rather than hardware. Four states set a ceiling. California regulates the opposite end — not the price, but the share of it you carry. Most publish nothing we could verify. We went through every published figure we could find and put the rule or filing behind each one.
Taking the device out costs nothing in Virginia and $150 in Illinois
Removal is the cleanest comparison in this whole area: identical work, identical hardware, no room for a state to argue its drivers are different. Virginia caps it at zero — a provider there may not charge you to take the device out at all. Delaware folds removal into the installation fee and rebates $30 of it back when the device comes off. Elsewhere it is a line item like any other.
| Jurisdiction | Removal | How the figure is set |
|---|---|---|
| Virginia | $0 | capped by regulation — removal is capped at $0 — a Virginia provider may not charge you to take the device out 24VAC35-60-50. Fees — Virginia Administrative Code |
| Delaware | $0 | capped by regulation — covered by the installation fee DE Admin. Code 2223 — Ignition Interlock Device Installation, Removal and Monthly Fees |
| Tennessee | $75 | capped by regulation Rules of Ignition Interlock Device Program, Chapter 1340-03-06 — TN Department of Safety |
| Georgia | $75 | capped by regulation Rules of the Department of Driver Services, Subject 375-3-6 — Ignition Interlock Devices |
| Washington | $100 | state guidance Ignition Interlock Device Compliance and Monitoring — Washington JLARC report |
| Oklahoma | $89–150 | filed vendor schedule Smart Start Oklahoma State Pricing Schedule — Oklahoma Board of Tests |
| Illinois | $150 | state guidance — de-install labor on the filed LifeSafer schedule About the Breath Alcohol Ignition Interlock Device — Illinois Secretary of State |
The four jurisdictions that set a ceiling
A cap is not a discount scheme — it is the maximum a licensed provider may lawfully charge for what the regulation names. Read the wording before assuming it covers your whole bill: it usually does not.
Virginia
- Installation: $65 — standard install; $130 for hybrid or push-button start, $75 to move the device to another vehicle
- Monthly: $95 — plus applicable taxes; includes the fees the provider owes the commission
- Removal: $0 — removal is capped at $0 — a Virginia provider may not charge you to take the device out
24VAC35-60-50. Fees — Virginia Administrative Code · checked 2026-08-23
Tennessee
- Installation: $225 — billed hourly — up to $75 per hour, three hours maximum
- Monthly: $125 — covers lease, monitoring and maintenance
- Removal: $75
Rules of Ignition Interlock Device Program, Chapter 1340-03-06 — TN Department of Safety · checked 2026-08-23
Delaware
- Installation: $100 — includes removal at the end of the program, and $30 of it is rebated back to you when the device comes out
- Monthly: $75 — monitoring and calibration
- Removal: $0 — covered by the installation fee
DE Admin. Code 2223 — Ignition Interlock Device Installation, Removal and Monthly Fees · checked 2026-08-23
Georgia
- Installation: $75 — the same cap applies to de-installation or a secured deposit
- Monthly: $75 — inspection and recalibration every 30 days
- Removal: $75
Rules of the Department of Driver Services, Subject 375-3-6 — Ignition Interlock Devices · checked 2026-08-23
A capped fee is not a capped bill
A statute caps the thing it names and nothing else. Oklahoma is the clearest demonstration, because the question went all the way to the state Supreme Court. Oklahoma law caps the monthly interlock maintenance fee at $25. A driver paying $39 in lease, $25 in maintenance, $5.41 in sales tax and a $5 damage waiver argued that the cap had plainly been exceeded, and sued.
He lost. In February 2016 the court held that the cap covers maintenance alone and does not limit rental, tax or damage-waiver charges — the legislature could have capped those and did not. His bill came to more than triple the capped figure and was entirely lawful.
Source: Heath v. Guardian Interlock Network, 2016 OK 18, Oklahoma State Courts Network, checked 2026-08-30
So read the cap wording rather than the headline. Virginia’s monthly ceiling is expressly “plus applicable taxes”; its removal cap, by contrast, is a real zero, and a Virginia provider may not charge you to take the device out at all. When a quote arrives in a capped state, the question is not whether the total exceeds the cap but which line the cap is attached to.
California regulates your share instead of the price
California caps nothing. Since January 2019 it fixes how much of the provider’s price lands on the driver, indexed to the federal poverty level, and puts the remainder on the provider rather than the taxpayer.
| Your income | Your share of the provider’s standard program cost |
|---|---|
| Income at or below 100% of the federal poverty level | driver pays 10% |
| Income at 101–200% of the federal poverty level | driver pays 25% |
| Income at 201–300% of the federal poverty level, or receiving CalFresh | driver pays 50% |
| Income at 301–400% of the federal poverty level | driver pays 90% |
| Everyone else | driver pays 100% |
Two things make this worth reading closely. The percentages apply to the provider’s own standard program cost, which California does not regulate — a share of an unregulated number is still an unregulated number. And the statute carries a penalty for silence: the Department of Consumer Affairs may fine a provider up to $1,000 for failing to tell a driver the schedule exists, which is not a rule anyone writes unless drivers were not being told.
California Vehicle Code § 23575.3(k) — fee schedule by income · checked 2026-08-26
Help that exists but rarely gets mentioned
Several states pay part of the cost for drivers who cannot afford it, or waive their own fees. None of it is automatic, and a provider quoting you a monthly price has little reason to bring it up.
| Jurisdiction | What is available | Amount |
|---|---|---|
| Oklahoma | Missed appointment | $55 (waived with 24 hours notice) |
| Maryland | Program enrollment fee | $47 (waivable on medical or food assistance) |
| Washington | Financial assistance for low-income drivers | up to about $1,400 reimbursed; the $21 monthly fee is waived |
| Washington | Device transfer to another vehicle | assistance up to $100 a year |
| New Mexico | Indigent assistance — installation | up to $50 paid by the state |
| New Mexico | Indigent assistance — monthly | up to $30 for verified active use |
| New Mexico | Indigent assistance — removal | up to $50 |
What the remaining states publish
Some publish only their own administrative fees and leave the device price to the provider. One publishes a filed vendor schedule instead of a cap. The rest publish nothing we could verify.
How this was built, and what it cannot tell you
Every figure comes from a state regulation, a vendor schedule filed with a state, or a state agency’s own published guidance, and every one is linked to the document it came from, so you can check it rather than take our word. All of them were verified against the source in August 2026. Where a state publishes nothing, we say so instead of estimating.
Three limits. A cap is a ceiling, not the price you will be quoted. Figures published as guidance are what an agency observed, not what a provider must honor. And this covers the device only — court fines, treatment programs and the insurance filing that usually follows a conviction are all separate, and together they normally exceed the device.
For a national reference point, NHTSA’s driver guide puts installation at $70–90 and monthly monitoring at about $70. Treat it as a floor rather than a current price: that edition was published in 2019, and it is a federal average, not a rule anyone is bound by.
Reuse it freely, with a link back. If you want a state we have not covered, ask and we will go and find what it publishes.