How Long Will Alcohol Show Up on a Breathalyzer Test?

Alcohol shows up on a breathalyzer for as long as it's in your blood. For most people, reading drops by about 0.015 per hour after drinking stops. Virginia's Department of Forensic Science puts the typical range at 0.010 to 0.020 per hour. At that rate, someone at 0.10 would take somewhere between 5 and 10 hours to get back to zero.

If you were just arrested in Georgia, that's only part of the picture. Georgia's DUI law is built around a three hour window, and the breath machine at the station has rules it has to follow before its number counts against you.

A breath test measures alcohol in air from deep in your lungs. That alcohol comes from your blood, so your breath reading falls as your liver clears alcohol from your bloodstream.

Your personal rate varies. Research by forensic toxicologist A.W. Jones found that people who drank on an empty stomach cleared alcohol more slowly than people who had eaten. Heavy drinkers in detox cleared it much faster than average.

At the average rate of 0.015 per hour, rough times to reach zero look like the following:

• 0.08: about 5 hours
• 0.10: about 6 to 7 hours
• 0.15: about 10 hours

These are estimates built on an average. Your body may run faster or slower.

There is no reliable countdown you can run in your head. Alcohol keeps absorbing into your blood after your last drink, so your level can still be climbing during the stop and at the station.

In Georgia, that climb usually doesn't help you. Under O.C.G.A. § 40-6-391(a)(5), you commit per se DUI if your alcohol concentration is 0.08 or more at any time within three hours after driving, from alcohol you drank before driving ended. For drivers under 21, the limit is 0.02. A 0.09 at the jail an hour after the stop can support the charge even if you were lower behind the wheel.

Timing still matters in two ways:

• Drinking after driving. Alcohol you drank after you stopped driving doesn't count toward the per se charge.
• Unclear timelines. The state has to connect your result to the three hours after you drove. If it can't pin down when you were driving, the per se count gets harder to prove.

A per se charge is also separate from "less safe" DUI, which is based on impairment rather than a number.

Here's my rewrite, restructured into prose:
Georgia police use the Intoxilyzer 9000 for evidential breath tests. The machine is precise when it's run correctly, but problems usually come from how the test was run.

The first thing to look at is the waiting period. The GBI's Intoxilyzer 9000 operator training directs officers to hold a 20 minute observation period before the test, with no eating, drinking, smoking, or medication, while watching for signs of regurgitation. That wait exists for a reason. Research on mouth alcohol found it clears within about 15 minutes, so if the officer cut the wait short or wasn't paying attention, alcohol still sitting in your mouth can inflate your result.

Reflux and burping raise the same concern. A 2025 case report described a person who burped repeatedly before the test and reported acid reflux, and the test was run anyway. When stomach contents come back up, they can carry alcohol into your mouth and skew the reading.

Georgia law also sets rules for the test itself. Under O.C.G.A. § 40-6-392, officers must request two breath samples in sequence, and the readings must fall within 0.020 of each other to be admissible. When they do, the lower number controls. The same statute gives the GBI's Division of Forensic Sciences authority to issue operator permits and set requirements for maintaining and certifying each instrument, which means your attorney can request the officer's permit and the machine's maintenance records to check whether both were in order.

A breath test is evidence, not a verdict. The questions that decide whether it holds up are specific: when you had your last drink, when you stopped driving, when you blew, whether anyone watched you for the full 20 minutes, and whether the machine's records are clean.

Your license is on a separate, faster clock. Under Georgia's implied consent law, you have 30 days to request an administrative license suspension hearing and pay a $150 fee, or you lose the right to that hearing.

Michael Fulcher was a former prosecutor and an assistant district attorney prosecuting thousands of DUI and traffic cases in Georgia. He knows how the state builds a breath test case, and where those cases fall apart.

If you were arrested in Morgan, Greene, Putnam, Jasper, or Taliaferro County, call us for a free consultation.