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

In Texas, you are considered legally intoxicated if your blood alcohol concentration (BAC) reaches 0.08% or higher while driving. This limit applies to anyone 21 years old or older operating a motor vehicle on a public road. Texas Penal Code § 49.01 defines intoxication as having a BAC of 0.08% or more, or being impaired to the extent that you cannot safely operate a vehicle — whichever applies first.

The 0.08% threshold is the same across all 50 states and has been federal law since 2000. However, Texas law also allows prosecution for driving while intoxicated (DWI) at any BAC level if an officer observes signs of impairment — slurred speech, poor coordination, failed field sobriety tests, or erratic driving. You do not have to blow a 0.08% to be arrested and charged.

Drivers under 21 face a zero-tolerance rule: any detectable alcohol in their system while driving is illegal under Texas Transportation Code § 106.041. Drivers with a commercial license (CDL) are held to a 0.04% limit under federal regulations, regardless of the vehicle they are driving at the time.

Key Takeaways

  • Texas law sets 0.08% BAC as the legal intoxication limit for drivers 21 and older, matching the federal standard.
  • You can be arrested for DWI at any BAC level if an officer observes impairment, even below 0.08%.
  • Drivers under 21 cannot legally have any measurable alcohol in their system while driving.
  • Commercial drivers are subject to a 0.04% BAC limit, half the standard limit for non-commercial drivers.
  • Texas law distinguishes between "intoxicated" (0.08% or higher) and "impaired" (unable to safely operate a vehicle), and either can result in DWI charges.

How Texas measures and tests blood alcohol concentration

Texas law enforcement uses three primary methods to measure BAC: breath tests (breathalyzers), blood tests, and urine tests. Breath tests are the most common roadside tool and measure the amount of alcohol in your breath, which correlates to blood alcohol. Blood tests are more precise and are often used after arrest or when breath results are disputed. Urine tests are the least common and typically used only when breath and blood tests are unavailable.

When you are pulled over, an officer may ask you to perform a breath test at the roadside (the preliminary alcohol screening test) before arrest. This roadside breath test result is not always admissible in court, but it can be used to establish probable cause for arrest. After arrest, you will be offered a breath or blood test at the police station or jail — this is the official test that becomes evidence in any prosecution.

Texas has an "implied consent" law: by driving on Texas roads, you are deemed to have consented to a breath or blood test if arrested for DWI. Refusing the test carries separate penalties, including automatic license suspension and the refusal itself can be used against you in court as evidence of consciousness of guilt.

DWI charges and penalties at different BAC levels

Texas law does not create separate charges based on BAC level — a DWI is a DWI whether your BAC is 0.09% or 0.20%. However, BAC level affects sentencing and can influence whether you face a misdemeanor or felony charge depending on prior convictions and circumstances.

A first DWI offense with BAC of 0.08% to 0.15% is typically a Class B misdemeanor, punishable by up to 180 days in jail and a fine up to $2,000. If your BAC is 0.15% or higher on a first offense, some prosecutors may charge it as a Class A misdemeanor (up to one year in jail, up to $4,000 fine). A second DWI within 10 years is a Class A misdemeanor. A third DWI within 10 years becomes a felony (2 to 10 years in prison).

Beyond criminal penalties, a DWI conviction results in a mandatory driver's license suspension: 90 days to two years for a first offense, depending on whether you refused the breath or blood test. You may be required to install an ignition interlock device on your vehicle, which prevents the car from starting if it detects alcohol on your breath. Texas also assesses surcharges of $1,000 to $2,000 per year for three years following a DWI conviction.

The difference between "intoxicated" and "impaired" in Texas law

Texas Penal Code § 49.01 defines intoxication in two ways, and either one can support a DWI charge. The first is a BAC of 0.08% or higher. The second is a state of impairment — meaning you do not have the normal use of your mental or physical faculties because of alcohol, drugs, or a combination of both. This second definition means you can be charged with DWI even if your BAC is below 0.08%.

An officer does not need a breath or blood test to establish impairment. Field sobriety tests (the walk-and-turn, one-leg stand, and horizontal gaze nystagmus tests), observations of slurred speech, bloodshot eyes, poor balance, or admission of drinking can all be used to prove impairment. This is why some people are arrested and convicted of DWI with a BAC of 0.05% or 0.06% — the prosecution proved impairment without relying on the 0.08% threshold.

The distinction matters because it means the 0.08% limit is a legal floor, not a ceiling. Texas law casts a wider net by also prosecuting drivers who are impaired below that threshold. Conversely, a very high BAC (0.15% or above) can be used to enhance penalties or support more serious charges in some cases.

Ignition interlock devices and BAC monitoring

Texas requires an ignition interlock device (IID) on any vehicle you own or regularly drive following a DWI conviction. An IID is a breathalyzer connected to your vehicle's ignition system. Before the engine starts, you must blow into the device. If it detects alcohol above a set threshold (typically 0.02% to 0.04%, well below the legal driving limit), the vehicle will not start.

The mandatory IID period depends on your BAC at the time of arrest and your prior record. For a first offense with BAC below 0.15%, the minimum IID period is six months. If your BAC was 0.15% or higher, or if you refused the breath or blood test, the minimum is one year. Second and subsequent offenses carry longer mandatory periods, up to two years or more.

You pay for the IID installation and monthly monitoring fees, which typically range from $60 to $150 per month. The device records all test results and violations (attempts to start the vehicle with alcohol detected). These records are reported to the Texas Department of Public Safety and can be reviewed by the court or your probation officer.

Prescription drugs, over-the-counter medications, and DWI

Texas DWI law is not limited to alcohol. You can be charged with DWI for driving under the influence of drugs — including prescription medications, over-the-counter drugs, and illegal substances. The law does not require a specific BAC equivalent for drugs; instead, the prosecution must prove you were impaired and unable to safely operate a vehicle.

Common medications that can impair driving include sedating antihistamines (Benadryl), certain antidepressants, pain medications containing opioids, anti-anxiety drugs, and sleep aids. Even if you are taking a medication as prescribed by a doctor, you can still be charged with DWI if the medication impairs your ability to drive. The label warning "do not operate machinery" is a signal that the drug may affect driving ability.

Drug-related DWI cases often rely on a Drug Recognition informed (DRE) — a specially trained officer who performs a 12-step evaluation to identify drug impairment. Unlike breath or blood tests for alcohol, there is no single chemical threshold for drug impairment, which means these cases can be more subjective and more difficult to defend or prosecute.

Challenging BAC test results in Texas

BAC test results are not automatically accurate or admissible in court. Texas law allows defendants to challenge the reliability and accuracy of breath and blood tests through several avenues. For breath tests, common challenges include whether the device was properly calibrated, whether the officer was certified to operate it, whether the test was administered correctly (typically requiring a 15-minute observation period before the test), and whether the defendant's individual physiology affected the result.

Blood tests can be challenged on chain-of-custody grounds (whether the sample was properly stored and handled), whether the lab was certified, whether the technician was may have access to, and whether the sample was contaminated or degraded. Texas requires that blood samples be drawn by a may have access to person — typically a nurse, phlebotomist, or physician — and that the sample be preserved with an anticoagulant and preservative to prevent fermentation or bacterial growth that could artificially raise the BAC reading.

If you refused the breath or blood test, that refusal cannot be used as direct evidence of guilt in Texas criminal court (though it can be used in a civil case and affects licensing). However, the refusal itself may be admissible to show consciousness of guilt, and the prosecution can still pursue a DWI conviction based on other evidence of impairment.

Frequently Asked Questions

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

Yes. Texas law allows DWI arrest and prosecution based on impairment alone, without a BAC of 0.08% or higher. If an officer observes signs of impairment — slurred speech, poor coordination, failed field sobriety tests — you can be arrested and charged even if your BAC is 0.05% or 0.06%. The 0.08% threshold is a legal presumption of intoxication, not a requirement for arrest.

What happens if I refuse a breath or blood test in Texas?

Refusing the test triggers automatic administrative penalties: your driver's license is suspended for 180 days on a first refusal, or two years if you have a prior DWI or refusal. The refusal itself cannot be used as evidence of guilt in the criminal case, but it can be used in a civil case and shows consciousness of guilt. You can still be prosecuted for DWI based on other evidence of impairment.

Does Texas have a "wet reckless" plea option?

Texas does not have a formal "wet reckless" charge. However, prosecutors may offer to reduce a DWI charge to reckless driving or another lesser offense in exchange for a guilty plea. This is a negotiated outcome, not a statutory option, and depends on the specific facts of your case and the prosecutor's discretion.

Can I drive with a BAC between 0.05% and 0.08%?

Legally, yes — you are not presumed intoxicated below 0.08%. However, you can still be arrested and convicted of DWI if an officer observes impairment. Studies show that impairment begins at lower BAC levels for some people, and an officer can use field sobriety tests and observations to establish impairment below 0.08%.

What is the BAC limit for commercial drivers in Texas?

Commercial drivers are subject to a 0.04% BAC limit under federal law, regardless of whether they are driving a commercial vehicle at the time of the stop. A CDL holder can face DWI charges at 0.04% or higher, and conviction can result in loss of the commercial license for at least one year on a first offense.