How long does marijuana/THC stay in your system?

For a urine test: single use is detectable for about 3 days, moderate use (4 times per week) for 5-7 days, daily use for 10-15 days, and chronic heavy use for 30 or more days. Hair tests can detect THC for up to 90 days. Saliva tests detect THC for 24-72 hours. THC is stored in fat cells, so people with higher body fat and heavier use patterns will test positive for longer periods.

How long does cocaine stay in your system?

Cocaine is detectable in urine for 2-4 days after a single use, or up to 14 days with heavy/binge use. The metabolite benzoylecgonine is what urine tests actually detect. In hair, cocaine is detectable for up to 90 days. Saliva tests detect it for 1-3 days. Blood tests detect cocaine for only 12-24 hours.

What is the most common type of drug test for employment?

The urine test (urinalysis) is by far the most common drug test for employment. It is used for the standard DOT 5-panel test, most pre-employment screenings, and workplace testing programs. Oral fluid (saliva/mouth swab) tests are becoming more popular, especially for retail and warehouse jobs, because they are easy to administer and detect recent use. Hair tests are less common but used by some employers for safety-sensitive positions.

Can drinking water help you pass a drug test?

Drinking excessive water before a urine test can dilute the sample, potentially lowering metabolite concentrations below the cutoff level. However, labs test for dilution by measuring creatinine levels and specific gravity. If your sample is flagged as too dilute, you will typically be required to retest. Extremely dilute samples may be treated as a refusal to test. Normal hydration will not significantly affect results.

How accurate are home drug tests?

FDA-cleared home drug tests (available at pharmacies for $10-$30) are reasonably accurate when used correctly and use the same cutoff levels as lab-based initial screens. However, they can produce false positives, which is why lab tests use a confirmation step (GC-MS or LC-MS/MS). A negative home test is a good indicator. A positive home test should be confirmed by a lab.

What is the difference between a 5-panel and 10-panel drug test?

A 5-panel test screens for marijuana (THC), cocaine, opioids, amphetamines, and PCP. This is the standard DOT test and most common employment test. A 10-panel test adds benzodiazepines (Xanax, Valium), barbiturates, methadone, propoxyphene, and methaqualone. The 10-panel is more commonly used by government agencies, law enforcement, and some healthcare employers.

Can secondhand marijuana smoke cause a positive drug test?

It is extremely unlikely. Studies show that even extended exposure to secondhand marijuana smoke in a poorly ventilated room does not typically produce THC metabolite levels above the standard 50 ng/mL cutoff used in most urine tests. You would need to be in an enclosed space with very heavy smoke for an extended period to approach the cutoff level.

How long do opioids stay in your system?

Most opioids are detectable in urine for 1-4 days. Heroin and morphine: 1-3 days. Codeine: 1-3 days. Oxycodone (OxyContin, Percocet): 2-4 days. Hydrocodone (Vicodin): 2-4 days. Methadone: 3-7 days (up to 14 days with chronic use). Fentanyl: 1-3 days. Hair tests can detect opioids for up to 90 days. Note that fentanyl may not appear on a standard 5-panel test — it requires specific testing.

Does CBD show up on a drug test?

Pure CBD (cannabidiol) does not show up on a standard drug test because tests screen for THC, not CBD. However, many CBD products — especially full-spectrum products — contain trace amounts of THC (up to 0.3% by law). Regular use of these products could potentially cause enough THC to accumulate and trigger a positive result. To minimize risk, use CBD isolate or broad-spectrum products that are certified THC-free.

What happens if I have a prescription for a drug that shows up on a test?

If you test positive for a substance you have a valid prescription for (such as Adderall, Xanax, or opioid pain medication), inform the Medical Review Officer (MRO) who reviews the result. The MRO will verify your prescription with your pharmacy and report the result as negative. You do not need to disclose prescriptions before the test. For DOT-regulated positions, some prescribed medications (like opioids) may still disqualify you from safety-sensitive duties even with a prescription.

Drug Test Detection Times — How Long Do Drugs Stay in Your System?

Last updated: 2026-03-21

How long a drug stays detectable depends on the substance, the type of test, and individual factors like frequency of use, body fat percentage, and metabolism. Urine tests are the most common and typically detect use within the past 1-30 days. Hair tests have the longest detection window at up to 90 days. Saliva tests detect the most recent use (12-72 hours). Blood tests have the shortest window (hours to a few days). Below is a comprehensive reference table for all major substances and test types.

Detection Times by Substance and Test Type

Substance	Urine	Hair	Saliva	Blood
Marijuana / THC	3-30 days	Up to 90 days	24-72 hours	1-2 days (THC); metabolites up to 25 days in heavy users
Cocaine	2-4 days	Up to 90 days	1-3 days	12-24 hours (cocaine); metabolites 1-2 days
Opioids (heroin, morphine, codeine)	1-3 days	Up to 90 days	24-48 hours	6-24 hours
Amphetamines (Adderall, meth)	1-5 days	Up to 90 days	24-72 hours	24-72 hours
Benzodiazepines (Xanax, Valium, Klonopin)	1-7 days	Up to 90 days	1-3 days	6-48 hours
PCP (Phencyclidine)	5-14 days	Up to 90 days	1-3 days	24 hours - 7 days
Barbiturates	2-7 days	Up to 90 days	1-3 days	1-3 days
Methadone	3-7 days	Up to 90 days	24-48 hours	24-72 hours
Fentanyl	1-3 days	Up to 90 days	24-48 hours	5-48 hours
Alcohol (Ethanol)	12-48 hours (EtG test: up to 80 hours)	Up to 90 days (EtG marker)	12-24 hours	Up to 12 hours

Detailed Urine Detection — Varies by Usage Pattern

Marijuana / THC: Single use: 3 days. Moderate use (4x/week): 5-7 days. Daily use: 10-15 days. Chronic heavy use: 30+ days.
Cocaine: Single use: 2-4 days. Heavy/binge use: up to 14 days. Metabolite (benzoylecgonine) detectable longer than parent drug.
Opioids (heroin, morphine, codeine): Heroin/morphine: 1-3 days. Codeine: 1-3 days. Hydrocodone: 2-4 days. Oxycodone: 2-4 days.
Amphetamines (Adderall, meth): Amphetamine (Adderall): 1-3 days. Methamphetamine: 3-5 days. MDMA/Ecstasy: 1-3 days.
Benzodiazepines (Xanax, Valium, Klonopin): Short-acting (Xanax, Ativan): 1-4 days. Long-acting (Valium, Klonopin): 5-7 days. Chronic use: up to 30 days.
PCP (Phencyclidine): Single use: 5-7 days. Chronic use: up to 14-30 days.
Barbiturates: Short-acting: 2-4 days. Long-acting (phenobarbital): up to 7 days or longer.
Methadone: Standard detection: 3-7 days. Chronic maintenance use: up to 14 days.
Fentanyl: May not appear on standard 5-panel tests — requires specific fentanyl testing. Detection: 1-3 days.
Alcohol (Ethanol): Standard urine: 12-24 hours. EtG (ethyl glucuronide) metabolite test: 48-80 hours after last drink.

Drug Test Types Explained

Urine Test (Urinalysis / UA)

Detects drug metabolites (breakdown products) that the body excretes through urine. The most widely used drug testing method.

Detection window: 1-30 days depending on substance

Pros: Most common and accepted; relatively long detection window; well-established cutoff levels; FDA/SAMHSA approved; inexpensive ($30-$60 per test).

Cons: Can be affected by hydration level; does not detect very recent use (takes 2-6 hours for metabolites to appear); privacy concerns with observed collections.

Used by: Most employers, DOT-regulated testing, probation/parole, court-ordered testing.

Hair Follicle Test (Hair drug test)

Detects drug metabolites that are deposited into hair follicles through the bloodstream. A 1.5-inch hair sample represents approximately 90 days of history.

Detection window: Up to 90 days (does not detect use within the last 5-7 days)

Pros: Longest detection window; very difficult to cheat; good for detecting patterns of use over time; not affected by short-term abstinence.

Cons: Does not detect very recent use (last 5-7 days); more expensive ($100-$150 per test); potential for environmental contamination (secondhand smoke); concerns about racial bias (darker hair may retain more metabolites).

Used by: Some employers (especially for safety-sensitive roles), insurance companies, custody cases.

Saliva / Oral Fluid Test (Mouth swab test)

Detects the parent drug (not metabolites) in saliva. A swab is placed between the gum and cheek for 2-5 minutes.

Detection window: 12-72 hours depending on substance

Pros: Easy to administer; non-invasive; detects very recent use; difficult to cheat (observed collection); quick results; now approved for DOT testing (since 2023).

Cons: Short detection window (misses use beyond 2-3 days); relatively new for some testing programs; limited detection for some substances.

Used by: Amazon, many retailers, law enforcement roadside testing, DOT-regulated testing (since 2023).

Blood Test (Blood drug test)

Detects the active parent drug and metabolites in the bloodstream. Requires a blood draw by a medical professional.

Detection window: Hours to a few days

Pros: Most accurate at detecting current impairment; precise quantitative results; difficult to cheat.

Cons: Invasive (requires needle); shortest detection window; expensive; requires trained phlebotomist; impractical for most workplace testing.

Used by: Hospitals, DUI/DWI investigations, accident investigations, insurance claims.

Factors That Affect Detection Times

Frequency of Use: The most significant factor. A single use of marijuana may be detectable for 3 days in urine, while daily chronic use can be detectable for 30+ days. This is because THC is stored in fat cells and released slowly over time. The same principle applies to benzodiazepines and other fat-soluble drugs.
Body Fat Percentage: THC and some other substances are stored in fat cells (they are lipophilic). People with higher body fat percentages may retain detectable levels of THC for longer periods. This is less of a factor for water-soluble drugs like cocaine and amphetamines.
Metabolism / Metabolic Rate: People with faster metabolisms break down and excrete drugs more quickly. Factors that affect metabolism include age (younger people metabolize faster), physical activity level, overall health, and genetics. Exercise can temporarily increase the release of THC from fat cells.
Hydration Level: For urine tests, hydration significantly affects results. Heavily diluted urine may produce a negative result even when drugs are present, but labs check for dilution (creatinine levels, specific gravity). If your sample is flagged as dilute, you may need to retest. Dehydration can concentrate metabolites and extend the apparent detection window.
Drug Dosage and Potency: Higher doses and more potent substances take longer to be fully metabolized and excreted. For example, high-potency THC concentrates will be detectable longer than a single hit from a low-THC product.
Route of Administration: How a drug is taken affects detection times. Smoking or injecting produces rapid onset but may have different metabolite profiles than oral ingestion. Edible marijuana, for example, produces higher levels of the metabolite 11-OH-THC, which is then converted to THC-COOH (the metabolite tested for in urine).
Age and Health: Older individuals and those with liver or kidney conditions may metabolize drugs more slowly, extending detection windows. Liver function is particularly important because most drug metabolism occurs in the liver.
Drug Interactions: Some medications can slow the metabolism of other drugs, extending detection times. For example, certain antidepressants and antifungal medications inhibit liver enzymes that metabolize other substances.

Understanding Drug Test Panels: 5-Panel vs. 10-Panel vs. 12-Panel

Drug tests come in different panel configurations. A 5-panel test is the most common for employment and screens for marijuana (THC), cocaine, opioids, amphetamines, and PCP — this is the standard DOT test. A 10-panel test adds benzodiazepines, barbiturates, methadone, propoxyphene, and methaqualone. A 12-panel test further adds extended opioids (oxycodone, hydrocodone) and MDMA/ecstasy. Some employers use expanded panels that also include fentanyl, tramadol, or synthetic cannabinoids. Always ask which panel is being used if you are concerned about specific substances.

Cutoff Levels — What Makes a Test Positive

Drug tests use cutoff levels measured in nanograms per milliliter (ng/mL) to determine a positive result. For example, the standard SAMHSA cutoff for THC in urine is 50 ng/mL for the initial screen and 15 ng/mL for the confirmation test. This means that trace amounts below the cutoff will NOT trigger a positive result. Federal workplace and DOT tests use SAMHSA-established cutoff levels. Some private employers may use lower cutoffs. A positive initial screen is always confirmed with a more precise test (GC-MS or LC-MS/MS) before being reported.

The DOT 5-Panel Test — Standard for Regulated Employers

The Department of Transportation requires a specific 5-panel test for all safety-sensitive employees (CDL drivers, pilots, train operators, etc.). This test screens for: marijuana (THC) at 50 ng/mL initial / 15 ng/mL confirmation; cocaine at 150 ng/mL / 100 ng/mL; opioids (codeine, morphine, heroin) at 2000 ng/mL / 2000 ng/mL; amphetamines (including methamphetamine and MDMA) at 500 ng/mL / 250 ng/mL; and PCP at 25 ng/mL / 25 ng/mL. DOT tests must follow strict chain-of-custody procedures and are reviewed by a Medical Review Officer (MRO) before results are reported.

Prescription Medications and Drug Tests

If you take a prescribed medication that may cause a positive drug test (such as Adderall for ADHD, opioid pain medication, or benzodiazepines for anxiety), you should disclose your prescription to the Medical Review Officer (MRO) who reviews positive results. The MRO will verify your prescription and report the result as negative. You do NOT need to disclose prescriptions before the test — only if the test comes back positive. For DOT tests, having a valid prescription for an opioid may not be sufficient — CDL drivers are prohibited from using certain medications while performing safety-sensitive duties.

Frequently Asked Questions

How long does marijuana/THC stay in your system?: For a urine test: single use is detectable for about 3 days, moderate use (4 times per week) for 5-7 days, daily use for 10-15 days, and chronic heavy use for 30 or more days. Hair tests can detect THC for up to 90 days. Saliva tests detect THC for 24-72 hours. THC is stored in fat cells, so people with higher body fat and heavier use patterns will test positive for longer periods.
How long does cocaine stay in your system?: Cocaine is detectable in urine for 2-4 days after a single use, or up to 14 days with heavy/binge use. The metabolite benzoylecgonine is what urine tests actually detect. In hair, cocaine is detectable for up to 90 days. Saliva tests detect it for 1-3 days. Blood tests detect cocaine for only 12-24 hours.
What is the most common type of drug test for employment?: The urine test (urinalysis) is by far the most common drug test for employment. It is used for the standard DOT 5-panel test, most pre-employment screenings, and workplace testing programs. Oral fluid (saliva/mouth swab) tests are becoming more popular, especially for retail and warehouse jobs, because they are easy to administer and detect recent use. Hair tests are less common but used by some employers for safety-sensitive positions.
Can drinking water help you pass a drug test?: Drinking excessive water before a urine test can dilute the sample, potentially lowering metabolite concentrations below the cutoff level. However, labs test for dilution by measuring creatinine levels and specific gravity. If your sample is flagged as too dilute, you will typically be required to retest. Extremely dilute samples may be treated as a refusal to test. Normal hydration will not significantly affect results.
How accurate are home drug tests?: FDA-cleared home drug tests (available at pharmacies for $10-$30) are reasonably accurate when used correctly and use the same cutoff levels as lab-based initial screens. However, they can produce false positives, which is why lab tests use a confirmation step (GC-MS or LC-MS/MS). A negative home test is a good indicator. A positive home test should be confirmed by a lab.
What is the difference between a 5-panel and 10-panel drug test?: A 5-panel test screens for marijuana (THC), cocaine, opioids, amphetamines, and PCP. This is the standard DOT test and most common employment test. A 10-panel test adds benzodiazepines (Xanax, Valium), barbiturates, methadone, propoxyphene, and methaqualone. The 10-panel is more commonly used by government agencies, law enforcement, and some healthcare employers.
Can secondhand marijuana smoke cause a positive drug test?: It is extremely unlikely. Studies show that even extended exposure to secondhand marijuana smoke in a poorly ventilated room does not typically produce THC metabolite levels above the standard 50 ng/mL cutoff used in most urine tests. You would need to be in an enclosed space with very heavy smoke for an extended period to approach the cutoff level.
How long do opioids stay in your system?: Most opioids are detectable in urine for 1-4 days. Heroin and morphine: 1-3 days. Codeine: 1-3 days. Oxycodone (OxyContin, Percocet): 2-4 days. Hydrocodone (Vicodin): 2-4 days. Methadone: 3-7 days (up to 14 days with chronic use). Fentanyl: 1-3 days. Hair tests can detect opioids for up to 90 days. Note that fentanyl may not appear on a standard 5-panel test — it requires specific testing.
Does CBD show up on a drug test?: Pure CBD (cannabidiol) does not show up on a standard drug test because tests screen for THC, not CBD. However, many CBD products — especially full-spectrum products — contain trace amounts of THC (up to 0.3% by law). Regular use of these products could potentially cause enough THC to accumulate and trigger a positive result. To minimize risk, use CBD isolate or broad-spectrum products that are certified THC-free.
What happens if I have a prescription for a drug that shows up on a test?: If you test positive for a substance you have a valid prescription for (such as Adderall, Xanax, or opioid pain medication), inform the Medical Review Officer (MRO) who reviews the result. The MRO will verify your prescription with your pharmacy and report the result as negative. You do not need to disclose prescriptions before the test. For DOT-regulated positions, some prescribed medications (like opioids) may still disqualify you from safety-sensitive duties even with a prescription.

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Take Action — Direct Links

SAMHSA — Drug testing guidelines and cutoff levels
Federal guidelines for workplace drug testing programs
DOT drug testing regulations (49 CFR Part 40)
Federal regulations for DOT-mandated drug testing
FDA — Drugs of Abuse Home Use Test
FDA information on over-the-counter drug tests
SAMHSA National Helpline — 1-800-662-4357
Free, confidential 24/7 treatment referral and information (English & Spanish)
FMCSA Drug & Alcohol Clearinghouse
Check your CDL drug testing record — all DOT violations are tracked here

Disclaimer: This is informational only, not medical advice. Detection times are approximate and vary based on individual factors. This guide is intended to help you understand drug testing, not to help circumvent testing. If you are struggling with substance use, call SAMHSA at 1-800-662-4357 (free, confidential, 24/7).