What is an Interlock Device?

As a condition of bail a magistrate may order the defendant to install a breath alcohol device or interlock for certain offenses on any vehicle that the defendant drives. An interlock is an electronic device wired into the ignition system of a vehicle which requires the user to pass a breath alcohol test in order to start the vehicle.

If the defendant is ordered by the magistrate to install an interlock device on his/her vehicle, the defendant will have to pay a fee to the monitoring agency to monitor the device. The fee is generally $10.00 per month. The defendant will also pay a monthly lease fee for the device. The monthly lease fee will vary depending on the interlock company.

Who monitor’s the device?

The monitoring agency for the magistrate’s office is the Personal Bonds (PR) Office. The PR bonds office does not accept personal checks or cash. Make cashier’s check or money order out to “Williamson County” in the amount of $10.00.

If the defendant does not install the device within the time ordered by the magistrate or fails to pay the monthly fee a warrant may be issued for his/her arrest and the bail may be raised.

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.

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

In Person
306 West 4th, Georgetown, Texas 78628.

Williamson County Personal Bond Office
405 Martin Luther King Blvd, Box 19, Georgetown, Texas 78626.
Include defendant’s Name, DOB and Sheriff’s Office Number (SO#) is the number assigned to the defendant while in custody.

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

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 [email protected] if defendant’s case was never assigned to a court. Defendant should notify the PR bonds office immediately at [email protected] 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.