California DUI: How to Subpoena Breathalyzer Records

You were pulled over, arrested, and asked to blow into a machine. That machine determined you were over the legal limit, and now you are facing a DUI charge. But have you ever stopped to ask: Was the machine working correctly?

At The Win Law Firm, we know that breathalyzers are not infallible. They are sensitive electronic devices that require rigorous upkeep. In California, if the police failed to maintain that device according to strict state laws, your test results—and potentially your entire case—could be thrown out.

One of the most powerful tools in a DUI defense is the subpoena. Below, we break down exactly how we access the “black box” of breathalyzer data to fight for our clients in Nevada County and beyond.

Why Do These Records Matter?

Before we dive into the how, it is vital to understand the why.

In California, breath testing is governed by Title 17 of the California Code of Regulations. These regulations are not suggestions; they are mandatory. Title 17 requires that every breath testing instrument used by law enforcement be:

• Calibrated every 10 days OR after every 150 uses (whichever comes first).
• Tested for accuracy using a known reference sample.
• Operated by a trained officer.

If the “Custodian of Records” (the person in charge of the logs) cannot prove the machine met these standards at the time of your arrest, the accuracy of your Blood Alcohol Concentration (BAC) reading is in doubt.

Can I Just Ask for the Records?

Yes and no. When you are arraigned, the prosecution provides an initial “discovery packet.” This usually includes the police report and your specific breath test strip. However, it rarely contains the historical maintenance logs or calibration records of the device.

To get the full history of the machine, your attorney must dig deeper.

Step 1: The Informal Discovery Request

The first step in the process is not a subpoena, but a formal letter to the District Attorney (DA). We request:

• Maintenance logs for the specific device (identified by serial number) for the months leading up to and following your arrest.
• Accuracy check records.
• Repair history (has this machine broken down before?).
• Usage logs (how many people blew into it before you?).

Step 2: The Subpoena Duces Tecum

If the DA cannot or will not produce the records (often because they are held by a forensic lab or a specific police agency and not the DA’s office), we move to the Subpoena Duces Tecum.

A Subpoena Duces Tecum is a court order that commands a specific person or entity to produce documents.

The Process:

1. Drafting the Subpoena: We identify the specific agency holding the device (e.g., the Nevada County Sheriff’s Department or a state forensic lab).
2. Filing with the Court: The subpoena is issued by the attorney (as an officer of the court) or signed by a court clerk.
3. Service: The subpoena must be personally served to the “Custodian of Records” at the relevant agency.
4. Timeline: In California, this must generally be served at least 15 days before the court hearing date to give the agency time to comply.

Step 3: The Motion to Compel

What happens if the police ignore the subpoena? It happens more often than you might think. If the agency refuses to hand over the calibration logs, we file a Motion to Compel.

This is a request to the Judge to force the agency to release the evidence. If they continue to refuse, we can argue for sanctions—including the exclusion of the breath test evidence entirely.

What Are We Looking For in the Logs?

When we receive these documents, we look for “red flags” that prove the machine was unreliable:

• The “Gap”: Was the machine checked on day 1 and then not again for 14 days? If your arrest happened on day 12, the machine was out of compliance with Title 17.
• Drift: Did the machine consistently read 0.09% when tested with a 0.10% solution? This shows the sensors were degrading.
• Error Codes: Do the logs show repeated “error” messages or “abort” codes in the days before your arrest?

How Does This Help My Case?

If we find a violation of Title 17, we can file a motion to suppress the breath test evidence. Without the BAC number, the prosecution’s case often crumbles, leading to:

• Dismissal of charges.
• Reduction to a “Wet Reckless”.
• Acquittal at trial.

Why You Need a Former Prosecutor on Your Side

Navigating the bureaucracy of government agencies, forensic labs, and the court system requires experience. As a former prosecutor, our lead attorney Kenny Nguyen knows exactly how the state tries to hide or minimize these maintenance issues. We know where to look, what to ask for, and how to read the technical data once we get it.

Don’t let a machine decide your future. If you suspect the breathalyzer in your case was faulty, you need aggressive representation immediately.

Ready to fight your DUI charges?

Time is critical. Evidence can be lost, and strict deadlines apply to subpoenas. Contact The Win Law Firm today for a consultation. Let us put our experience to work for you.

Disclaimer: This blog post is for informational purposes only and does not constitute legal advice. Always consult a licensed attorney for guidance specific to your case.

Frequently Asked Questions (FAQ)

1. How much does it cost to subpoena breathalyzer records?

The cost can vary. While the issuance of the subpoena by your attorney is part of your legal service, the agency (police or lab) is allowed to charge “reasonable costs” for the time and materials used to locate and copy the records. This is typically a nominal fee, but it is an essential investment in your defense.

2. Can I subpoena these records myself?

Technically, yes, if you are representing yourself (“pro per”). However, the rules regarding the formatting, service, and timing of a Subpoena Duces Tecum are complex. A single procedural error can result in the judge quashing (canceling) your subpoena. It is highly recommended to have a licensed attorney handle this process.

3. What if the records show the machine was working perfectly?

Even if the machine was calibrated correctly, the administration of the test might have been flawed. Did the officer observe you for 15 continuous minutes? Did you have mouth alcohol from burping? Calibration is just one angle of attack; we investigate them all.

4. Does Title 17 apply to the roadside breath test (PAS)?

Generally, the Preliminary Alcohol Screening (PAS) device used at the roadside is considered a field sobriety test and is subject to slightly different standards than the “evidentiary” station breathalyzer. However, if the PAS results are being used as primary evidence (common in underage DUI cases), Title 17 maintenance standards typically apply.

5. How far back should the records go?

We typically request records for at least a few weeks prior to your arrest and a few weeks after. This allows us to establish a pattern of behavior for the machine. If it was acting up two weeks before your arrest and broke down two days after, it is strong evidence that it was malfunctioning during your arrest.