How Long Does Detox Take? By Substance, Setting, and New Jersey Data

How long does detox take?

In a New Jersey residential detox, about a week. The state’s 2024 treatment data put the median stay at 7 days and the average at 8, across 15,500 discharges and all substances.

That number hides two different questions. One is how long withdrawal lasts, which depends mostly on the drug. The other is how long a person stays in a detox program, which depends on the setting, the person’s health, and what comes next. Withdrawal decides how short a stay can safely be. Whether the stay helped depends on what happens the day after discharge.

How long detox takes, by substance

Alcohol

MedlinePlus says alcohol withdrawal symptoms tend to start within 8 hours of the last drink, peak by 24 to 72 hours, and may go on for weeks. The dangerous complications have their own clocks. Withdrawal seizures are most common in the first 12 to 48 hours, and delirium tremens most often starts 48 to 96 hours after the last drink but can start 7 to 10 days later. That late window is why a two-day alcohol detox can end before the riskiest stretch does. Our alcohol withdrawal timeline walks through it hour by hour.

Opioids

SAMHSA’s TIP 63 puts early withdrawal from short-acting opioids at 8 to 24 hours, full withdrawal at days 1 to 3, and a total of 7 to 10 days. For long-acting opioids such as methadone, early withdrawal can take up to 36 hours to appear and the total runs 14 days or more. Fentanyl is the exception that matters in New Jersey: after regular use it clears slowly, and in a 2020 study urine took about a week on average to test negative. See fentanyl withdrawal for what that does to the timeline.

With opioids, the length of detox is partly a choice. TIP 63 says buprenorphine or methadone can be used for a supervised withdrawal over days to weeks, that data conflict on the ideal length, and that its expert panel does not recommend short-term supervised withdrawal alone, because of high rates of return to illicit opioid use. It recommends offering ongoing medication instead, for years if it is helping.

Benzodiazepines

Benzodiazepine detox is the one where a week is the wrong unit. The 2025 joint tapering guideline from ASAM and nine other medical groups says clinicians should not stop benzodiazepines abruptly in people likely to be physically dependent, that a taper should generally start with dose cuts of 5 to 10 percent every 2 to 4 weeks and typically not exceed 25 percent every 2 weeks, and that it may take months to years to taper off fully after long, high-dose use. The FDA warns that protracted withdrawal can persist beyond 4 to 6 weeks, with symptoms lasting weeks to as long as 12 months. An inpatient stay can stabilize the start. It cannot hold the whole taper. Our Xanax withdrawal guide covers why abrupt stops are dangerous.

Stimulants

The 2024 ASAM/AAAP stimulant guideline describes commonly 12 to 24 hours of heavy sleepiness and irritability, then post-acute symptoms, including depression, anxiety, insomnia, and paranoia, that can last weeks to months. The guideline also says suicidality may increase as the drug wears off and during acute withdrawal. Our cocaine comedown guide covers the crash.

How long detox takes, by setting

The setting names below come from the third edition of the ASAM Criteria, the placement standard New Jersey uses for addiction care, as the ASAM alcohol withdrawal guideline lists them. The New Jersey lengths come from the state’s 2024 data, which excludes outliers. The state reports its own categories (residential, outpatient non-methadone, and hospital detox), not ASAM levels, so matching them to the ASAM rows is our reading.

Read the hospital and outpatient rows with care: each rests on a few hundred discharges or fewer. Outpatient detox runs longer on the calendar because it is spread out. For alcohol, the ASAM guideline recommends daily check-ins for up to five days after someone stops drinking in an ambulatory setting. Our pages on outpatient detox and hospital detox cover each setting in New Jersey.

The fourth edition of the ASAM Criteria folds withdrawal management into its main levels. According to ASAM, Level 1-WM becomes 1.7, 2-WM becomes 2.7, 3.7-WM becomes 3.7, and 3.2-WM services fold into Level 3.5. A program or insurer may use either set of numbers.

What makes a detox stay longer or shorter

• The drug. Methadone runs longer than heroin or oxycodone, and fentanyl after regular use can too.
• More than one substance. In the ASAM alcohol guideline’s placement table, dependence on benzodiazepines rules out outpatient detox, and withdrawing from another substance at the same time is a reason for caution.
• Past withdrawals. The ASAM guideline calls it kindling: repeated alcohol withdrawals can become progressively more severe.
• Health and age. Unstable medical problems and severe psychiatric symptoms weigh against outpatient detox in the ASAM table, older age is listed as a factor to weigh, and the guideline says inpatient treatment should be considered for every pregnant patient who needs alcohol withdrawal management.
• Starting a medication. Beginning buprenorphine, methadone, or naltrexone changes what discharge means: the person leaves on a treatment, not just off a drug.
• Leaving early. A stay cut short by the patient is still a stay, and it shows up in the median. Our page on leaving detox early covers what that costs.

Is detox enough on its own?

Detox treats withdrawal. It does not treat the addiction. The state’s 2024 data shows what happens at the door: of 15,550 detox discharges, excluding ambulatory detox, 48 percent transferred to another level of care at the same agency, 8 percent had continuing care set up with a new agency, and 19 percent refused continuing care.

That 19 percent is the group to worry about, especially after opioids. Opioid withdrawal is rarely fatal by itself, though tolerance falls within days, so a return to a former dose can be fatal. The lofexidine (Lucemyra) label warns that people who complete opioid discontinuation have an increased risk of fatal overdose if they use again. Ask on day one what the plan is for day eight. Our guide to what comes after detox lays out the options.

How fast can you get into detox in New Jersey?

Often fast, though not always. In the 2024 data, 94 percent of people admitted to residential detox waited 0 to 1 day. That figure only counts people who got in. Whether a bed is open today depends on the program, the plan, and the hour you call. On fully insured New Jersey plans, New Jersey law P.L.2017, c.28, requires the plan to make an exception to its network when no in-network facility is immediately available, so that admission can happen within 24 hours.

How long will insurance pay for detox in New Jersey?

Under New Jersey law P.L.2017, c.28, fully insured New Jersey plans and the State Health Benefits and School Employees’ plans cannot require prior authorization for the first 180 days per plan year of in-network treatment your own physician, psychologist or psychiatrist finds medically necessary, or, during those same 180 days, for outpatient prescription drugs that treat substance use disorder, such as buprenorphine and naltrexone, when that clinician finds them medically necessary. Self-funded employer plans, Medicare and Medicaid are not covered by that rule, so verify with the plan.

On those same plans, the law also sets a clock for inpatient care:

• The first 28 days of an inpatient stay each plan year get no concurrent or retrospective review of medical necessity; the covered person’s physician decides.
• From day 29, the plan may run concurrent review, but no more often than every two weeks, and the request to continue has to be filed before day 28 ends.
• If the plan decides more inpatient care is not medically necessary, it must give written notice within 24 hours, and the expedited internal and external appeals are each decided within 24 hours. The person cannot be discharged until those appeals are exhausted.

With a median of 7 days, a detox stay rarely reaches day 29 on its own. The 28-day rule matters more when detox rolls straight into residential treatment; ask the plan how it counts those days, because the law counts the first 28 inpatient days per plan year. The state’s Department of Banking and Insurance says inpatient care under the law is not limited to hospitals. It can be any lawfully operating facility accredited by the Joint Commission or approved by Medicare, and plans may also choose to recognize CARF-accredited or plan-credentialed facilities. Our insurance guides go plan by plan.

NJ FamilyCare covers medically supervised withdrawal. Residential detox is authorized through the IME for most members, outpatient and hospital detox go through the member’s health plan, and residential care and opioid treatment programs are scheduled to move into the NJ FamilyCare health plans in January 2027.

For help independent of us, the state’s IME Addictions Access Center at 1-844-276-2777 screens NJ FamilyCare and uninsured residents and refers them to treatment, and ReachNJ, the state treatment line, is at 1-844-732-2465. Periscope Behavioral Health, which publishes this site, is opening a medical detox in Hammonton, Atlantic County, expected Summer 2027. Until it opens, Periscope Behavioral Health at (888) 313-3583, our publisher’s admissions line, can talk through options in New Jersey and Florida, including facilities Periscope operates. What a plan covers depends on the plan and the facility’s network status.

Questions that tell you how long a program expects to keep you

1. What decides my discharge date: a set number of days, or my withdrawal scores?
2. If my withdrawal runs long, can I stay, and who asks the insurer?
3. Will I start a medication here, and who prescribes it after I leave?
4. Where do your patients usually go next, and can you book it before discharge?

If the answer to the first question is a number of days, ask the follow-up: what happens if withdrawal is not finished by then?