Last reviewed Oct 26, 2026. General information, not legal advice.
A breath alcohol test measures the alcohol in your breath with an approved device. Unlike a drug test, the result is known on the spot.
How a DOT breath test works
- ID and paperwork. You show a photo ID and the technician fills out the federal alcohol testing form.
- Screening test. You blow into a device through a new, sealed mouthpiece.
- If the screening result is low enough, you’re done.
- If not, you wait a short time and take a confirmation test on an evidential device. The confirmation result is the one that counts.
What the numbers mean
DOT rules set cutoffs. A very low reading is a pass. A reading in a middle range means the driver is pulled from duty for a short time. A higher reading is a violation, which starts the return-to-duty process.
When it’s done
DOT alcohol tests are done for random selections, after certain accidents, on reasonable suspicion, and for return-to-duty and follow-up. Pre-employment alcohol tests are usually up to the employer.
Before your test
Avoid mouthwash, breath spray, food and smoking right before the test.
Breath alcohol tests at our office
We offer non-DOT breath alcohol tests now, for $45 (Estimate, confirmed at booking; last updated Oct 27, 2026). DOT breath alcohol tests are not yet available. They start once our technician qualification is complete, at $55. You can join the waitlist on the service page.