Valium (diazepam) is detectable in urine for 1 to 7 days after a single dose and up to 30 days or longer after chronic use. That wide range exists because Valium produces active metabolites that linger in your body far longer than the drug itself, and several personal factors can push your detection window toward either end of the spectrum.
Single Use vs. Chronic Use
If you took Valium once or only a handful of times, expect it to show up on a urine test for roughly 5 to 10 days after your last dose. Some sources put the lower end at just 1 day for a very small dose in someone who clears drugs quickly.
Daily use over weeks or months is a different story. Regular dosing allows Valium and its breakdown products to accumulate in body fat and tissues, creating a reservoir that slowly releases back into your bloodstream. Someone who has been taking Valium daily for months can test positive for 30 days or longer after stopping. That is one of the longest detection windows of any benzodiazepine.
Why Valium Stays So Long
Valium itself has a half-life of 21 to 37 hours, meaning it takes that long for your body to eliminate half of a single dose. But your liver converts diazepam into several active metabolites: nordiazepam, temazepam, and oxazepam. Nordiazepam is the key one. Its half-life ranges from 36 to 200 hours, which at the upper end is over 8 days just to clear half of it. Your body needs roughly five half-lives to fully eliminate a substance, so nordiazepam alone can take weeks to disappear.
Standard urine drug screens look for these metabolites, not just the original drug. When all three (nordiazepam, temazepam, and oxazepam) appear together in a urine sample, labs interpret that pattern as consistent with diazepam use specifically.
Factors That Extend Your Detection Window
Not everyone clears Valium at the same rate. Several factors can push you toward the longer end of the detection window:
- Age: Older adults process Valium significantly more slowly. In elderly patients, the half-life of diazepam and its metabolites can stretch to 96 hours. After age 40, the liver’s first-pass metabolism declines by roughly 1% per year, and overall drug clearance through liver enzymes drops 30 to 40% with aging.
- Body fat: Diazepam is highly fat-soluble. People with more body fat have a larger reservoir where the drug can accumulate, increasing its effective half-life. Body fat naturally increases with age, compounding the effect.
- Liver function: Since your liver does the heavy lifting in breaking down diazepam, any condition that impairs liver function (or reduces blood flow to the liver, such as heart failure) will slow clearance. Smoking and certain medications that interact with the same liver enzymes can also alter processing speed in either direction.
- Dose and duration: Higher doses and longer periods of use mean more drug stored in tissues. A person taking 20 mg daily for six months will test positive far longer than someone who took 5 mg once.
How Urine Testing Works
Most urine drug screens use an immunoassay, which is a quick, relatively inexpensive test that flags the presence of a drug class rather than a specific medication. For benzodiazepines, the standard cutoff is either 200 or 300 nanograms per milliliter. Anything below that threshold registers as negative, even if trace amounts are technically present.
There is an important quirk with these immunoassay screens. Diazepam itself has relatively low cross-reactivity, meaning the test is actually more sensitive to detecting Valium’s metabolites (particularly oxazepam) than the parent drug. This is part of why detection windows are so long: even after diazepam itself is gone, its metabolites keep triggering positive results.
If an initial screen comes back positive, a confirmation test using mass spectrometry can identify exactly which benzodiazepine metabolites are present. This second test is more precise and can distinguish Valium from other benzodiazepines.
Benzodiazepines and Workplace Drug Tests
If you are concerned about a standard federal workplace drug test, benzodiazepines are not part of the federally mandated testing panel. The HHS drug testing guidelines (updated January 2025, effective July 2025) test for marijuana, cocaine, opioids, fentanyl, PCP, and amphetamines. Benzodiazepines are not included.
That said, many private employers, healthcare organizations, and clinical settings use expanded panels that do include benzodiazepines. Courts, probation programs, and pain management clinics routinely test for them as well. Whether your specific test screens for benzodiazepines depends entirely on who ordered it and why.
False Positives to Be Aware Of
Two common medications can trigger a false positive for benzodiazepines on immunoassay screens: oxaprozin (a prescription anti-inflammatory sold as Daypro) and sertraline (the antidepressant Zoloft). If you test positive and have not taken any benzodiazepine, either of these could be the cause. A confirmation test with mass spectrometry will distinguish a true positive from a false one, so requesting confirmatory testing is the straightforward way to resolve it.