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DWI Urine Tests

Police officers and district attorneys tend to rely on scientific evidence when it comes to DWI trials in the form of chemical testing. A commonly used chemical test for driving while intoxicated cases is urine analysis. This is when an officer brings you to a hospital, lab or police station and asks you to submit a urine sample to measure the alcohol in your system.

Urine analysis gives a more reliable reading than DWI breath analysis, but it still has some flaws. Many urine tests can give false results if certain circumstances arise. If a chain of custody has issues or medical procedures aren’t followed, the sample could end up being contaminated. Additionally, urine testing itself isn’t the best process to find an accurate blood-alcohol concentration (BAC). It can test positive for past substances used days or even weeks ago.

If you’ve undergone urine testing for DWI, it’s important you contact a skilled attorney.

DWI Defense Attorney for Urine Analysis in Conroe, TX

When law enforcement attempts to establish BAC they may ask you to submit to urine analysis. This process isn’t always effective and can lead to skewed results. If you were charged with DWI because of a failed urine test or you refused to submit to testing, we suggest you get in touch with the experienced and dedicated attorneys at Evans & Powell, PLLC.

Our criminal defense attorneys have been practicing for years and will do whatever needed to fight for your case. We have the right tools, attitude and resources to chart out an effective defense plan. Call us now at (713) 622 - 2000 to set up your first consultation free.

Evans & Powell, PLLC accepts clients throughout the greater Montgomery County area including Willis, New Caney, Splendora, Montgomery and Magnolia.

Overview of DWI Urine Tests in TX

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How Does Urine Testing Measure Blood-Alcohol Concentration (BAC)?

The state of Texas utilizes blood-alcohol concentration (BAC) to determine what a person’s impairment level is when driving. This can be measured through various chemical tests which can include urine analysis. Most people who are asked to submit to a DWI urine test are doing so because the officer suspects them of being under the influence of a controlled substance. This is because breathalyzers normally don’t pick up on illicit drugs, only alcohol.

Under Texas law, the urine analysis should measure the number of grams of alcohol per 67 milliliters of urine. Typically, urine testing gives a much more accurate result than breath analysis. However, the problem rests with how much information urine analysis can give.

Urine testing gathers data of all substances within your system. Some of these substances, such as marijuana, have terpenes that remain in your system for days and sometimes weeks. This means you could be charged with a DWI for consuming a substance days or weeks ago. In addition, human errors or contaminated samples can also lead to false results.

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Issues with Urine Testing for DWI Cases in Texas

Urinalysis isn’t the most dependable method for measuring a person’s present impairment level. The samples are very delicate so they can be contaminated easily if a person doesn’t know what they’re doing. It can also detect the terpenes of substances that were consumed in the past. Some of these terpenes can remain within the body for up to one month depending on factors such as metabolism and if the usage is random or chronic.

Listed below are some detection times for common controlled substances:

Type of Drug:Detection Time
CocaineOne day
Lysergic Acid Diethylamide (LSD)One day
MDMA, Ecstasy, or MollyTwo days
KetamineTwo days
CodeineThree Days
AmphetamineThree Days
HydrocodoneThree Days
FentanylThree Days
MethamphetamineThree Days
OxycodoneThree Days
MorphineThree Days
FlunitrazepamFive Days
Moderate Marijuana UseFive Days
MethadoneSeven Days
Phencyclidine (PCPEight days
Diazepam10 days
Marijuana Daily Use10 days
Marijuana Chronic Use30 days


Some human errors or equipment issues can also lead to false results including:

  • Contaminated testing samples;
  • Improper storage;
  • Using expired testing kits;
  • Faulty testing kits; or
  • Diluted sampled

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What Can Happen If I Refuse a Urine Test in Texas?

The Texas statutes regarding chemical testing is known as implied consent laws. These state that any person who is using Texas’s public roads is also implicitly agreeing to submit to chemical testing by law enforcement. It’s imperative you remember that field sobriety testing isn’t included when it comes to implied consent laws. Only DWI chemical tests such as urinalysis, breath analysis and blood analysis apply.

Refusing to submit to a DWI urine analysis test can lead to an administrative penalty, which will be a license suspension. The length of the suspension depends on if you have any prior refusals. If you refuse urine testing, you license could be suspended up to:

  • 180 days for a first-time refusal; and
  • 2 years for a second or subsequent refusal

In Texas, it’s a burden to be without a car. However, it’s the best choice to refuse to urine testing and face a suspension rather than criminal charges. Refusing to submit to testing will mean the district attorney will only have access to objective evidence such as the police officer’s testimony. They won’t have any concrete scientific evidence against you. The prosecutor may not even take the case to trial if there’s no BAC reading present because they believe they can’t win the case without more tangible evidence.

An officer may intimidate you and try to say if you refuse DWI testing you will lose your license and go to jail. What they’re not going to tell you is that if you fail you will also lose your license and likely go to jail as well as face criminal DWI charges. Because of these reasons, many attorneys would advise you not to take your chances and just refuse.

If you submit to urine testing and fail, you license could be suspended up to:

  • 90 days for the first offense; and
  • 1 year for a second or subsequent offense

Thankfully, you may not have to deal with a suspended license for long. You can choose to contest your license suspension by requesting an administrative license revocation hearing (ALR). At the hearing, you can present evidence and bring legal representation to prove why you shouldn’t have your license revoked. It’s important you act quickly though. You will only have 15 days to request an ALR hearing. After the deadline is up, you will be prohibited by the Texas Department of Public Safety from requesting an ALR hearing.

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Additional Resources

Texas DWI Laws – Visit the official website of Texas Statutes to learn more about driving while intoxicated (DWI) and implied consent laws. Access the site to learn more about DWI charge specifics, enhancements, penalties for DWI refusal and the associated penalties of DWI.

Administrative License Revocation Program – Visit the official website of the Texas Department of Public Safety (DPS) to learn more about DWI license suspension as well as occupational licenses. Learn the suspension terms for non-commercial drivers, minors and commercial drivers and what an occupational license can do for you. You can find a link to file a request for an administrative license revocation hearing.

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Urine Analysis Lawyer in Montgomery County, Texas

If you have been arrested because of a failed or fault DWI urine analysis test, it’s our best advice that you contact Evans & Powell, PLLC. At Evans & Powell, PLLC, we have a special focus on driving while intoxicated cases and law. With our skills and resources, our defense team can create holes in the prosecution’s case to reduce or dismiss your DWI charges.

You can contact us now at (713) 622 - 2000 for quality legal representation. We will sit you with one of our practiced attorneys and discuss how we will tackle your case. You can find us in Conroe, but our lawyers accept clients throughout the greater Montgomery county area such as New Caney, Splendora, Willis and Montgomery


Evans & Powell, PLLC