If you are on a deferred prosecution for a Washington DUI and things go sideways, one of the first questions people ask is what happens to the ignition interlock.
Do you have to start over? Install it again? Serve more time on it?
Thanks to a new Washington DUI law that took effect January 1, 2026, the answer is much better than it used to be.
The Short Answer
If you already completed your ignition interlock requirement while on deferred prosecution, you generally should not have to reinstall the device if your deferred prosecution is later revoked.
The time you already served counts.
What Is Deferred Prosecution?
A deferred prosecution is a treatment-based alternative to a DUI conviction in Washington. Instead of pleading guilty, you agree to a long-term treatment program with strict conditions, including installing an ignition interlock device (IID).
If you complete the program, the DUI is dismissed. If you do not, the deferred prosecution can be revoked and you are convicted.
The Old Problem
Before this law change, a revoked deferred prosecution could be a nightmare for drivers who had already done their time on the interlock.
You could complete a full year on the device, remove it, and move on with your life. Then if your deferred prosecution was later revoked, you could face a brand new IID requirement on top of what you already served.
For a lot of people, that felt like being punished twice for the same DUI.
What Changed Under ESHB 1493
Washington passed a new DUI law, House Bill 1493 (ESHB 1493), effective January 1, 2026.
Under the new law, the Department of Licensing no longer stacks a second IID requirement on top of what you already completed during deferred prosecution. Instead, the new requirement is treated as the same length as your original IID period.
Because of that, the time you already served is credited.
A Real-World Example
Here is how this plays out:
- You enter deferred prosecution
- You install an ignition interlock device for one year
- You complete the requirement and remove the device
- Later, your deferred prosecution is revoked and you are convicted
Under the current approach:
- The DOL may impose a one-year IID requirement on paper
- You receive full credit for the time you already served
- You do not need to reinstall the device
- You are treated as already in compliance
Why This Matters
This is one of the most practical improvements to Washington DUI law in recent years.
Before, people who made a mistake during deferred prosecution could face years of additional IID restrictions, even after already complying once.
Now, the result is more predictable. If you already completed your IID requirement, that time counts.
What You Should Do If You Are in This Situation
Every case is different. Your outcome can depend on:
- Whether your deferred prosecution has already been revoked
- How much time you served on the IID
- Your compliance history with the device
- How DOL processes your court record
Do not guess. A wrong assumption about your license or your interlock can cost you months of driving or unnecessary reinstallation fees.
Talk to a Vancouver DUI Lawyer
If you have questions about ignition interlock requirements, deferred prosecution, or your driver’s license after a DUI in Washington, I can help.
Call (360) 975-4673 for a consultation, or use the contact form on this site to reach me directly.
This post is general information about Washington DUI law and is not legal advice. Reading it does not create an attorney-client relationship. For advice about your specific case, consult a licensed Washington attorney.