Texas sets 0.08% as the legal limit for drivers 21 and older

In Texas, you are considered legally impaired if your blood alcohol concentration (BAC) reaches 0.08% or higher while driving. This limit applies to anyone 21 or older operating a motor vehicle on a public road. Texas law treats a BAC of 0.08% as the threshold for driving under the influence, regardless of whether you feel impaired.

The 0.08% standard is federal law, adopted by all 50 states. Texas enforces this limit through its Driving While Intoxicated (DWI) statute. A police officer can stop you for suspected DWI based on your driving behavior alone — you do not have to be at or above 0.08% to be arrested. The BAC measurement itself becomes evidence used in court.

Texas also has a "zero tolerance" law for drivers under 21. Anyone under 21 with any detectable alcohol in their system — even 0.01% — can be charged with DWI. For commercial drivers, the limit is lower: 0.04% BAC while operating a commercial vehicle.

Key Takeaways

  • The legal BAC limit for drivers 21 and older in Texas is 0.08%, the same as every other state.
  • Drivers under 21 face zero tolerance: any measurable alcohol in their system can result in a DWI charge.
  • Commercial drivers must stay below 0.04% BAC while operating a commercial vehicle.
  • You can be arrested for DWI below the 0.08% threshold if an officer observes impaired driving behavior.
  • BAC is measured through breath, blood, or urine tests, and refusing a test carries separate legal penalties in Texas.

How BAC is measured and what counts as a test

Texas law allows three methods to measure BAC: breath tests (like a breathalyzer), blood tests, and urine tests. Breath tests are the most common roadside tool. If you are arrested, police typically request a blood test, which is more accurate and admissible in court. Urine tests are less common and usually only ordered if breath and blood are unavailable.

When you are pulled over, an officer may ask you to take a breath test at the roadside before arrest — this is called a preliminary alcohol screening (PAS) test. You can refuse this roadside test without automatic penalty, though refusal may be used as evidence of consciousness of guilt. After arrest, however, Texas law requires you to submit to either a breath or blood test under the state's implied consent law. Refusing this post-arrest test carries mandatory penalties separate from any DWI conviction.

Blood tests are drawn at a police station, hospital, or certified facility and sent to a lab for analysis. Results typically take weeks to return. Breath tests give when ready results but are less precise than blood tests. If you believe a test was administered incorrectly or the equipment was not properly maintained, your attorney can challenge the results in court.

What happens if you are stopped and suspected of DWI

A police officer can stop you if they observe signs of impaired driving: weaving, speeding, slow reaction time, or other traffic violations. During the stop, the officer will look for physical signs of intoxication — slurred speech, red eyes, smell of alcohol, or poor balance. They may ask you to perform field sobriety tests, such as walking in a straight line or following a pen with your eyes.

You have the right to refuse field sobriety tests without automatic legal consequence, though refusal may give the officer probable cause to arrest you anyway. If the officer believes they have enough evidence, they will arrest you and take you to a police station or jail for a breath or blood test. At this point, you must choose: submit to the test or refuse it.

If you submit and your BAC is 0.08% or higher, you will likely be charged with DWI. If you refuse the test, you will not have a BAC number in evidence, but Texas law imposes an automatic driver's license suspension and the refusal itself can be used against you in court. Either way, you will be booked, and bail or bond will be set before you can leave custody.

Penalties for DWI at or above 0.08% BAC

A first DWI conviction in Texas carries a minimum fine of $300 and up to $2,000, plus jail time of up to 180 days. Your driver's license will be suspended for at least 90 days. You will also be required to install an ignition interlock device on your vehicle — a breathalyzer that prevents the engine from starting if it detects alcohol on your breath.

A second DWI conviction within 10 years increases penalties: a fine of $600 to $2,000, jail time of 5 days to one year, and a license suspension of at least one year. A third or subsequent conviction is a felony in Texas, with a fine up to $10,000, prison time of 2 to 10 years, and a license suspension of at least two years.

Beyond criminal penalties, a DWI conviction affects your insurance rates, employment prospects, and professional licenses. Some employers conduct background checks that flag DWI convictions. If you hold a commercial driver's license, a DWI conviction will disqualify you from driving commercially, sometimes permanently.

Implied consent and what refusing a test means

Texas's implied consent law states that by driving on a public road, you have already consented to a breath or blood test if arrested for DWI. This means you cannot straightforward refuse without consequence. If you refuse a post-arrest test, your driver's license will be suspended for at least 180 days on a first refusal, and up to two years on a subsequent refusal within 10 years.

A refusal also triggers an automatic administrative license suspension separate from any criminal case. You have 15 days from the date of arrest to request a hearing with the Texas Department of Public Safety to contest the suspension. If you do not request a hearing within this window, the suspension takes effect automatically.

In court, the fact that you refused a test can be presented as evidence. Prosecutors may argue that refusal suggests consciousness of guilt. However, refusal also means there is no BAC number to prove you were above 0.08%, which can make the prosecution's case harder to prove. An attorney can advise you on the specific circumstances of your arrest.

Differences between DWI and DUI in Texas

Texas does not use the term "DUI" for adult drivers. Instead, the state uses "DWI" (Driving While Intoxicated) for anyone 21 or older. DWI applies whether you are impaired by alcohol, drugs, or a combination of both. The 0.08% BAC threshold applies only to alcohol; there is no equivalent legal limit for drugs, though impairment from drugs alone can still result in a DWI charge.

For drivers under 21, Texas uses "DUI" (Driving Under the Influence), which carries zero tolerance for any alcohol. A driver under 21 with a BAC of 0.01% or higher can be charged with DUI. The penalties for underage DUI are generally less severe than for adult DWI, but a conviction still results in license suspension and a criminal record.

Texas also has an "Intoxication Assault" charge if you cause injury while intoxicated, and "Intoxication Manslaughter" if someone dies. These are felonies with much harsher penalties than standard DWI.

Factors that affect how quickly you reach 0.08% BAC

Your BAC depends on several factors beyond the number of drinks consumed. Body weight, food intake, metabolism, and the time span over which you drink all affect how fast alcohol enters your bloodstream and how long it stays there. A person who weighs 120 pounds will reach a given BAC faster than someone who weighs 200 pounds after the same number of drinks. Eating food slows alcohol absorption.

Gender also plays a role: women typically reach higher BAC levels than men after drinking the same amount, because women have less body water and different enzyme levels. Medications, fatigue, and medical conditions can also change how your body processes alcohol. These factors mean there is no universal rule for "how many drinks equal 0.08%." The only reliable way to know your BAC is to measure it.

Texas law does not recognize impairment as a defense to DWI if your BAC is 0.08% or higher. Even if you feel completely sober, a BAC at or above the legal limit is sufficient for conviction. Conversely, you can be convicted of DWI below 0.08% if an officer and prosecutor can prove you were impaired by alcohol or drugs.

Frequently Asked Questions

Can I be arrested for DWI if my BAC is below 0.08%?

Yes. Texas law allows DWI arrest and conviction based on impaired driving behavior alone, even if your BAC is below 0.08%. An officer can arrest you if they observe signs of impairment such as weaving, slurred speech, or poor coordination. The 0.08% threshold is a legal presumption of impairment, not a requirement for arrest.

What is the difference between a breath test and a blood test for BAC?

Breath tests measure alcohol in your lungs and give when ready results but are less precise. Blood tests directly measure alcohol in your bloodstream and are more accurate, but results take weeks. Blood tests are generally more reliable in court. You cannot choose which test you receive after arrest — the officer decides based on circumstances and equipment availability.

If I refuse a breath test, can the police force a blood test?

Police can obtain a warrant to draw blood if you refuse a breath test and they have probable cause to believe you are intoxicated. A warrant requires a judge's approval, which can usually be obtained quickly by phone. Refusing a test does not prevent police from getting a blood sample through a warrant; it only delays the process and adds a refusal charge to your record.

Does Texas have an "open container" law separate from DWI?

Yes. Texas prohibits open containers of alcohol in a vehicle, meaning any open bottle, can, or cup with alcohol must be in the trunk or a sealed area, not the passenger compartment. An open container violation is a separate misdemeanor from DWI, though both can be charged together. You can receive an open container ticket even if your BAC is below 0.08%.

What happens to my driver's license after a DWI arrest?

Your license is suspended when ready upon arrest under the administrative license suspension process, separate from any criminal case. You have 15 days to request a hearing to contest the suspension. If you do not request a hearing, the suspension becomes permanent pending the outcome of your criminal case. If convicted, additional suspension periods explore based on whether it is your first, second, or subsequent offense.