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Free California DUI tool

IID requirement checker.

Find out whether an ignition interlock device is required for your California DUI, how long you must keep it, what it costs to install and monitor, and how the monthly data reporting works. Covers Vehicle Code 23575.3. Free written report delivered to your inbox.

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Your IID requirement analysis is on its way. It covers whether an IID is required, how long, what it costs, how monitoring works, and how to complete the requirement.

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IID requirements under VC 23575.3

California has required ignition interlock devices for DUI convictions statewide since January 1, 2019, under Vehicle Code 23575.3. Previously, IID requirements varied by county through a pilot program, but the statewide law eliminated that inconsistency. Every California DUI conviction now triggers an IID requirement, and the duration scales with the severity of the offense. First offense without injury: 6 months. First offense with injury: 1 year. Second offense: 1 year. Third offense: 2 years. Fourth or subsequent: 3 years. The IID requirement applies to every vehicle the defendant drives, not just one designated vehicle. Driving any vehicle without an IID during the required period is a separate criminal offense.

What installation and monitoring actually involves

The IID is a breath testing device wired into your vehicle's ignition system. You must blow into it before the engine starts, and the device requires periodic random "rolling retests" while the vehicle is in motion. Installation by a DMV-approved vendor costs between $70 and $150. Monthly monitoring fees run $60 to $80 per month. The monitoring vendor downloads the device's data monthly and transmits a report to the DMV and, if required by a court order, to the probation department. The report shows all test results, including the date, time, BAC reading, and whether the test was passed, failed, or skipped. California has an indigent waiver program that can reduce the monitoring cost for low-income defendants, but it does not eliminate the requirement.

What a failed test means

The IID threshold in California is 0.025% BAC — below the legal limit but set at a level that detects any meaningful alcohol consumption. A failed test means the device recorded a reading at or above 0.025%. The device locks out for a period and requires a clean retest to start. The DMV receives notice of every failed test. Consequences depend on whether the failure is isolated or part of a pattern. A single failed test typically results in a DMV warning letter. Multiple failures, or any attempt to tamper with or bypass the device, can result in the IID requirement period being restarted from zero, an extension of the requirement, or a probation violation if the court ordered the IID as a condition of probation. Circumventing an IID — including having another person blow into it — is a misdemeanor under Vehicle Code 23247.

How to complete the IID requirement

When the required period is complete and all tests are clean, the monitoring vendor issues a compliance certificate. That certificate must be filed with the DMV along with a $15 completion fee. Once the DMV processes the filing and confirms completion, the IID restriction is removed from your driving record and you are no longer required to maintain the device. Failure to file the completion paperwork means the IID restriction remains on your record indefinitely. It is worth checking your DMV record approximately 60 days after filing to confirm the restriction has been properly removed. Some vendors handle the DMV filing on the defendant's behalf, but you should verify that it has actually been processed.

Common questions

What people ask about IID requirements

Do I need an IID for a first DUI in California?

Yes. Under Vehicle Code 23575.3, a first DUI conviction in California triggers a 6-month IID requirement. The IID must be installed in every vehicle you drive during that period. If you use the IID restricted license path through the DMV (rather than waiting out the full APS suspension), the IID requirement runs concurrently with your restricted license period. The requirement begins on the date you apply for the restricted license, not on the date of conviction or arrest.

Does the IID need to be in every car I drive?

Yes. The IID requirement under VC 23575.3 applies to every vehicle you operate, not just vehicles you own. If you drive a family member's car, a company vehicle, or any other vehicle during the requirement period, an IID must be installed in that vehicle before you drive it. There is a very limited employer exception for certain commercial driving situations, but it requires prior DMV approval and does not apply to ordinary driving. Driving any vehicle without an IID is a misdemeanor with significant penalties including suspension extensions.

What happens if I fail an IID test?

The device locks out temporarily and records the failed test. The vendor transmits the result to the DMV at the next monthly download. For a first isolated failure, the DMV typically sends a warning letter. For repeated failures, the DMV may restart the IID requirement clock or extend the period. If the court ordered the IID as a condition of probation, repeated failures can constitute a probation violation, which carries additional consequences including possible jail time. The IID threshold is 0.025% BAC, which is one to two standard drinks for most adults. Any alcohol consumption before driving creates risk of a failed test.

How much does an IID cost?

Installation runs $70 to $150 per vehicle depending on the vendor and vehicle type. Monthly monitoring fees are $60 to $80 per month per vehicle. If you drive multiple vehicles, each requires a separate IID at additional cost. Removal at the end of the requirement period runs $50 to $100. Total cost for a first-offense 6-month requirement in one vehicle is typically $500 to $700. California has a low-income waiver program through the DMV that caps costs based on income, but it requires an application and approval before installation. Vendors vary in price and reliability, so it is worth comparing DMV-approved vendors in your area.

Can I get the IID requirement waived?

The IID requirement under VC 23575.3 is mandatory and cannot be waived by a judge or the DMV based on inconvenience or financial hardship alone. The low-income assistance program can reduce costs but not eliminate the requirement. In cases where a defendant does not own or drive any vehicle, the court may accept a declaration to that effect, but the requirement reattaches the moment the defendant drives any vehicle. Attempting to operate without an IID when required is a misdemeanor. There is no exemption for medical necessity, work need, or any other circumstance outside the narrow employer commercial vehicle exception.

Is this checker legal advice?

No. The checker output is for informational purposes only and does not create an attorney-client relationship. Legal advice, meaning advice specific to your circumstances given by a licensed attorney who has reviewed the full record, comes only after a consultation. The free consultation creates no obligation to retain.

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