Ignition interlock requirements in Washington

Washington's interlock section starts with a list of circumstances in which the Department of Licensing must impose the restriction, and then sets the terms: one, five or ten years after a DUI, a removal test of 180 clean days, day-for-day credit for time already on a device, and an employer exemption with limits.

A list of triggers, not a rule

The section works by enumeration. The department must require that a person drive only a vehicle fitted with a functioning ignition interlock device on receipt of notice from a court that a restriction has been imposed on pretrial release; as a condition of issuing an ignition interlock driver's license; on notice that the person is participating in a deferred prosecution; and in further listed circumstances.

What follows from that structure is practical. There is no single Washington interlock term to look up, because the trigger determines the shape of the obligation. Your own order or notice names which limb of the section you are under, and that is the document to read.

The version now in force, and how long it lasts

When this page was first written, the copy of the section published by the Legislature was headed (Effective until January 1, 2026.), and this page declined to state a duration, a cost or a removal condition rather than quote terms from an expiring version. The section as published on 19 October 2026 carries no such header and reflects amendments through 2024, so the terms below are from the version now in force. Your offense date can still matter for older cases, and your notice is the authority on your own.

For a deferred prosecution or a conviction for DUI or physical control, the restriction lasts no less than one year for a person not previously restricted, five years after a prior restriction, and ten years after a prior five-year restriction — longer still where passengers under sixteen were in the vehicle. For the reduced-charge limbs, where the charge began as DUI and ended as negligent or reckless driving, it is no less than six months. A pretrial restriction lasts until the court authorises removal or a later restriction from the same incident takes over; one tied to an interlock license lasts while the license is valid; one ordered by a court lasts as the court says.

Time without a device does not count

For incidents on or after 9 June 2016, the period is tolled for any time the person has no device installed on a vehicle they own or operate — unless the department has found that a physical disability prevents them using one. A conviction for driving without a device or for circumventing one adds 180 days; if the period is already over, a new 180-day restriction is imposed.

The employer question, and why it is in the section at all

The heading of the Washington section lists, among its subjects, an employer exemption. It is worth knowing the concept exists even though this page does not state its terms.

The problem it addresses is ordinary. A restriction that attaches to the driver rather than to a vehicle would otherwise reach every vehicle that driver operates, including a works van, a truck or a bus that the employer owns and that is fitted with nothing. Legislatures generally deal with this by carving out a vehicle owned by an employer and driven in the course of employment, on conditions — usually notice to the employer and a record of it.

Washington's conditions, in the version now in force: no device is needed on vehicles owned, leased or rented by the employer — or in the employer's temporary care — and driven at the employer's direction during working hours, once the department has the employer's declaration and notes the exemption on the driving record. It does not cover a vehicle assigned to the driver alone and used only for commuting, and it does not cover the self-employed unless the vehicle is used only for the business.

Driving outside the exemption is driving without a device: a gross misdemeanor, with the employer exemption an affirmative defense the driver has to prove.

Removal, credit and the fee

The period ending is not enough. The restriction stays until the department receives a declaration from the device vendor certifying that none of the following happened in the 180 consecutive days before release:

• an attempt to start the vehicle at 0.04 or more — unless a retest within ten minutes was lower and the digital image shows the same person gave both samples;
• a missed random test — unless the image shows the driver was not in the vehicle;
• a failed random retest at 0.020 or more, with the same ten-minute retest exception;
• a missed appointment for maintenance, calibration, monitoring, inspection or replacement;
• removal of the device by anyone other than a technician certified by the Washington State Patrol.

A certified technician must also inspect the device at the end of the 180 days and find no sign of tampering. A single bad week near the end restarts the count, which is why the removal date is often later than the restriction's minimum.

Credit for time already on a device

Time with a device installed to hold an ignition interlock license counts day-for-day toward the later restriction from the same incident, and so does any time from the date of the incident with a device on every vehicle the person operates. If the credit covers the whole period and the removal test has been met, the department may waive further installation. It is time already spent; it is worth checking that it has been counted.

The fee

On top of the device costs, the restricted person pays a further twenty-one dollars a month through the device company to the state's ignition interlock revolving account, which the department may waive for a person who is indigent. A person living outside Washington may verify installation through a provider authorized where they live.

Where this does connect to the filing

The financial-responsibility side of a Washington case is separate, is in a different chapter, and has been read in full. The filing period is three years from the date proof was required, and the release requires the preceding three years to be clean of any conviction, bail forfeiture or infraction finding that would require or permit another suspension.

The license that lets a person drive on the device during a suspension is a separate instrument, the ignition interlock driver's license, and it is issued only to someone who has filed proof of financial responsibility; the interlock license guide quotes RCW 46.20.385.

That look-back structure is the reason the two obligations can end years apart. An interlock condition satisfied does nothing for the filing, and a new infraction during the filing period can push the release date out well past the device coming off the car. The Washington SR-22 page covers it properly.

Three routes into the same restriction

The listed triggers are not variations on one process. They come from different stages and they behave differently, which is why a single “Washington interlock rule” does not exist.

Pretrial release. A court imposes the restriction as a condition of release, before anything has been decided. It attaches to a charge rather than to a conviction, and it can therefore begin months before any outcome.

The interlock driver’s license. Here the restriction is a condition of a license being issued at all. This is the route that lets somebody drive during a period when the ordinary license is not available, and the restriction is the price of it.

Deferred prosecution. The restriction follows participation in a program rather than a sentence, so its shape is set by the program.

What follows for a reader is practical: the answer to “how long” depends on which of these you are in, and the document that put you there is the one that says.

Two chapters, and why they never agree

Washington splits this across the code in a way that produces most of the confusion.

The interlock restriction lives in the licensing chapter, and it is about what vehicle you may drive. The financial-responsibility requirement lives in a different chapter entirely, and it is about whether an insurer has told the state your cover exists. Different chapters, different triggers, different release tests, different end dates.

Nothing in the code requires the two to line up, and in practice they do not. A person can finish an interlock term and still be two years from the earliest release of their filing — particularly in this state, where the filing release depends on a clean rolling three-year look-back rather than on time served. The reverse also happens.

The mistake worth avoiding is treating one document as evidence about the other. The device coming off the car says nothing about the certificate, and a released certificate says nothing about the device.

What the filing certifies while all this is going on

$25,000 per person / $50,000 per accident / $10,000 property damage — 25/50/10, under RCW 46.29.090(1). The property-damage figure is the lowest of any state on this site, and it is worth a moment's thought before buying at the floor for three years.

Common questions