Medically reviewed by Mitchell Naficy, MD, Medical Director at Tru Dallas Detox & Recovery Center (Texas Medical Board license W1860). Reviewed October 2026.
Short answer: Norco (hydrocodone plus acetaminophen) usually stays in your system for about 1 to 3 days on a standard urine test. In a controlled study, a single 20 mg dose of hydrocodone was detectable in urine for roughly 1 to 2 days, and Mayo Clinic Laboratories puts the usual urine window for hydrocodone at 2 to 3 days after the last dose. Saliva usually turns positive within minutes and stays positive for about a day; hair can show use for months. Heavy or long-term use can stretch these windows.
| Test type | Hydrocodone (Norco) | Notes |
|---|---|---|
| Urine | About 1 to 3 days | Lab confirmation looks for hydrocodone, norhydrocodone and hydromorphone |
| Saliva (oral fluid) | Often positive within 15 minutes; about 30 hours on average after one dose | Based on a sensitive lab cutoff of 1 ng/mL |
| Blood | Often detectable within 30 minutes; generally a shorter window than saliva | Blood testing is less common for routine screening |
| Hair | Up to about 3 months (scalp hair) | Reflects a pattern of past use, not recent use |
| Oxycodone (for comparison, urine) | About 2 to 3 days | Also often missed by a basic opiate screen |
| Fentanyl (for comparison) | Needs a fentanyl-specific test | Not reliably detected by a standard opiate screen |
Sources: Cone et al., J Anal Toxicol 2013 (urine); Cone et al., J Anal Toxicol 2015 (oral fluid and blood); Mayo Clinic Laboratories, hydrocodone and oxycodone urine tests; StatPearls: Drug Testing. Windows are estimates and vary from person to person.
What is Norco?
Norco is a prescription tablet that combines two drugs: hydrocodone, an opioid pain reliever, and acetaminophen, the same ingredient in Tylenol. The FDA label says it is meant for pain severe enough to need an opioid when other options have not worked well enough.
When people ask how long Norco stays in their system, they almost always mean the hydrocodone part, because that is what drug tests look for. Acetaminophen clears quickly (its half-life is about 1.25 to 3 hours) and is not part of a standard drug screen.
How long does Norco last?
The effects and the detection window are two different things. The pain relief and drowsiness wear off within hours, but the drug and its breakdown products can still be found in your body for a day or more after that.
- Peak levels: In the FDA label’s pharmacokinetic data, hydrocodone reached its highest blood level about 1.3 hours after a dose.
- Dosing interval: The label’s usual adult dose is taken every 4 to 6 hours as needed, which reflects how long one dose is expected to help with pain.
- Half-life: Hydrocodone’s half-life in the label is about 3.8 hours, meaning the blood level drops by about half in that time. It takes several half-lives for a drug to be mostly cleared, which is why tests can pick it up long after you stop feeling it.
The label also notes that with ongoing use, tolerance can develop, and one of its first signs is that each dose seems to wear off sooner.
How long does hydrocodone stay in urine?
Urine is the most common test for Norco. Your liver breaks hydrocodone down mainly into norhydrocodone (through the CYP3A4 enzyme) and, to a smaller extent, hydromorphone (through CYP2D6), and your kidneys clear them, according to the FDA label.
In a controlled study of 12 healthy adults given one 20 mg dose of hydrocodone, urine detection times at a 50 ng/mL lab cutoff were about:
- 28 hours for hydrocodone itself
- 40 hours for norhydrocodone
- 26 hours for hydromorphone
Hydrocodone and norhydrocodone showed up in urine within 2 hours, and levels peaked 3 to 9 hours after the dose (Cone et al., 2013). Mayo Clinic Laboratories states that finding hydrocodone in urine generally points to use within the previous 2 to 3 days. People who take Norco regularly or in higher doses may test positive for longer.
How soon after taking Norco will saliva test positive?
Very quickly. In a controlled study, hydrocodone was often detected in oral fluid within 15 minutes of a single 20 mg dose and in blood within 30 minutes. At a sensitive 1 ng/mL cutoff, hydrocodone stayed detectable in saliva for about 30 hours on average, and saliva windows were longer than blood windows at every cutoff tested (Cone et al., 2015).
StatPearls describes saliva windows in general as typically up to about 48 hours, and blood windows as roughly 1 to 2 days. Hair is different: scalp hair usually reflects use over about the past 3 months, so it shows a history of use rather than very recent use.
Why Norco may not show up on a basic opiate screen
This is one of the most common sources of confusion. Many basic “opiate” immunoassays were built to detect morphine and codeine. StatPearls notes that the standard opiate screen may miss opioids with a different structure, including hydrocodone and oxycodone, and does not reliably detect fentanyl or methadone. SAMHSA’s guide to clinical drug testing says a morphine-specific test “will miss opioids, such as hydrocodone and hydromorphone.”
Because of this, labs and employers who need to know about hydrocodone use a broader opioid panel or a confirmation test (usually mass spectrometry) that looks for hydrocodone and its metabolites by name. Federal workplace testing rules, for example, list hydrocodone and hydromorphone as their own test group, with a different cutoff than codeine and morphine (49 CFR 40.85).
A few points about reading results:
- Hydromorphone in urine can come from hydrocodone, since it is one of its metabolites (Mayo Clinic Laboratories).
- Norhydrocodone in a sample helps show that hydrocodone was the drug actually taken (Cone et al., 2013).
- If you take Norco as prescribed, tell the person ordering the test. A medical review officer or prescriber can verify a valid prescription.
Factors that change how long Norco stays in your system
- How much and how often: StatPearls notes that chronic or heavy use can make drugs detectable for longer.
- Liver enzymes and other medicines: The FDA label warns that drugs that block CYP3A4 can raise hydrocodone levels. People also differ in CYP2D6 activity, which affects how much hydromorphone they make.
- Kidney function: Hydrocodone and its metabolites leave the body mainly through the kidneys.
- The test itself: The specimen type, what the test looks for and the cutoff all change the result. A sensitive lab test can detect lower levels for longer than a quick cup test.
- Urine concentration: StatPearls lists fluid intake and urine pH among the factors that change urine results.
Norco carries an FDA boxed warning for liver damage. Acetaminophen has been linked to acute liver failure, sometimes leading to transplant or death, and most cases involve more than 4,000 mg of acetaminophen a day, often from more than one product. Check the labels of cold, flu and sleep products for acetaminophen too. Taking extra Norco to get more of the opioid effect also means taking more acetaminophen.
Norco’s label lists slowed breathing, extreme sleepiness that can progress to stupor or coma, and constricted pupils as signs of overdose. The CDC adds being unable to wake up, choking or gurgling sounds, and discolored lips or nails. Mixing Norco with alcohol, benzodiazepines or other sedatives raises the risk. If you see these signs, call 911, give naloxone if you have it, keep the person on their side and stay with them. More detail: signs of an opioid overdose.
Worried about how much Norco you are taking? Tru Dallas Detox offers 24/7 medically supervised detox and residential treatment in Euless, between Dallas and Fort Worth. Calls are confidential.
How we can help
If you are taking Norco more often than prescribed, running out early or feeling sick when a dose wears off, that can be a sign of physical dependence. Stopping suddenly can cause opioid withdrawal, which the label describes as restlessness, watery eyes, runny nose, yawning, sweating, chills and muscle aches. Here is what opioid withdrawal feels like and how long it lasts.
At Tru Dallas Detox & Recovery Center in Euless, our prescription pill detox provides 24/7 medical supervision with physician oversight and nursing care to keep withdrawal as safe and comfortable as possible. For opioid use, medication-assisted treatment with Suboxone, Vivitrol or Sublocade can be used alongside therapy. After detox, residential rehab includes individual and group therapy, relapse-prevention work and family involvement. If outpatient care is a better fit, our team can assist in finding outpatient options. We accept many PPO plans, and you can verify your insurance online.
Frequently asked questions
How long does Norco stay in your urine?
Usually about 1 to 3 days. In a controlled single-dose study, hydrocodone was detectable in urine for about 28 hours and its metabolite norhydrocodone for about 40 hours. Mayo Clinic Laboratories says hydrocodone in urine generally means use within the past 2 to 3 days. Regular or heavy use can extend this.
How long does Norco last?
Hydrocodone levels peak about 1.3 hours after a dose, and the label’s usual dose is every 4 to 6 hours as needed. The half-life is about 3.8 hours, so the drug can still be detected on tests after the effects have worn off.
How soon after taking Norco will my saliva test positive?
Often within 15 minutes. In a controlled study, hydrocodone appeared in oral fluid within 15 minutes of a dose and stayed detectable for about 30 hours on average at a sensitive lab cutoff.
How long does hydrocodone stay in your system?
It depends on the test. Urine usually detects it for about 1 to 3 days, saliva for about a day, blood for a shorter time and scalp hair for up to about 3 months. Dose, frequency, liver enzymes, kidney function and the test’s cutoff all change the window.
Does Norco show up as an opiate on a drug test?
Not always. Many basic opiate screens are designed to detect morphine and codeine and may miss hydrocodone. Labs that need to detect it use a broader opioid panel or a confirmation test that looks for hydrocodone, norhydrocodone and hydromorphone specifically.
Last updated: October 2026. This page is general information, not medical advice. In an emergency, call 911. Sources: FDA, Norco prescribing information; Cone EJ et al., Prescription Opioids II, J Anal Toxicol 2013; Cone EJ et al., Prescription Opioids IV, J Anal Toxicol 2015; Mayo Clinic Laboratories, HYDCU; Mayo Clinic Laboratories, OXYCU; StatPearls, Drug Testing; SAMHSA, Clinical Drug Testing in Primary Care (TAP 32); 49 CFR 40.85; CDC, What to Do If You Think Someone Is Overdosing.
