What is an Interlock Device?

As a condition of release on bail, a Magistrate Judge may order a defendant to install an ignition interlock device on any vehicle driven. An interlock device is a deep-lung breath analysis mechanism designed to prevent the operation of a motor vehicle if alcohol is detected in the breath of the vehicle operator.

Frequently Asked Questions

What if I do not have a vehicle?

Notify your attorney who will should then notify the assigned court. You may hire your own attorney or request an appointed attorney if you cannot afford to hire your own attorney.

For procedure on Requesting a Court Appointed Attorney click here
For procedure on Requesting a Court Appointed attorney in Spanish click here

What if I get an occupational license while awaiting sentencing?

Defer to assigned courts process.

How to Pay Interlock Fee

No Cash or Personal Checks.

In Person

Pretrial Services
First Floor, Justice Center
405 Martin Luther King Jr. St.
Georgetown, TX 78626

Williamson County Pretrial Services
405 Martin Luther King Blvd, Box 19
Georgetown, Texas 78626.

Online (follow these instructions)
Choose Payment Type “Ignition Interlock Fee” from drop down menu
Sheriff’s Office Number (SO#) - the number assigned to the defendant while in custody.

Include defendant’s Name, DOB and Sheriff’s Office Number (SO#) - the number assigned to the defendant while in custody.

Money Orders and Cashier’s Checks should be payable to “Williamson County.”

Technical difficulties with the device

If you have questions regarding basic operation of the device such as physical installation, how to use or manage the device, how to transfer the device from one vehicle to another, physical removal or return of the device, please contact the ignition interlock company.


Defendant may request removal at ignition@wilco.org if defendant’s case was never assigned to a court. Defendant should notify the PR bonds office immediately at ignition@wilco.org if the case is transferred to other monitoring agency such as probation. Defendant’s attorney may request removal by order of the assigned court or magistrate.