Rehab has no fixed length. Withdrawal care usually takes days, a residential stay can run from a few weeks to many months, and outpatient care and medication often go on for months or longer.12 The number that matters most is total time in care: most people need at least three months to significantly cut back or stop.1
Where your loved one starts depends on a clinical assessment of what they need. After that, length should follow progress.
How long does each stage of treatment take?
Most people move through more than one level of care. Our overview of the levels of care explains what each one is; this table covers time only.
| Stage | Typical time | What changes it |
|---|---|---|
| Withdrawal (detox) | Heroin and other short-acting opioids: about 3–5 days. Methadone: up to 10 days.2 Alcohol: symptoms start 6–24 hours after the last drink; delirium tremens, if it happens, usually lasts 2–3 days.3 | The substance, amount and overall health. A benzodiazepine taper is planned over weeks or months.2 |
| Short-term residential | No set length. The original model was a 3–6 week inpatient phase followed by extended outpatient therapy1 | Progress, home situation, insurance approval |
| Long-term residential | Therapeutic communities plan stays of 6–12 months1 | Program model and the person’s needs |
| PHP | No set length. Medicare ties it to at least 20 hours of therapy a week, usually 4–8 hours a day5 | Progress; often a step down from residential |
| IOP | No set length. Medicare ties it to at least 9 hours of therapy a week4 | Progress; often a step down from PHP |
| Outpatient counseling and medication | Months or longer | Ongoing need |
Detox on its own does little to change long-term use.1 Ask any detox program where your loved one goes next; our page on medical detox and the handoff to treatment covers that step.
Is rehab always 28 or 30 days?
No. Twenty-eight days is a tradition. NIDA says there is no predetermined length of treatment, because people progress at different rates.1
Insurance helps keep the number alive. Federal guidance from 2017 asks states whose Medicaid programs pay for residential addiction treatment to aim for a statewide average stay of 30 days.8 That average is spread across many people and isn’t a cap on any one person’s care. Our page on who residential treatment is really for goes into the 28-day myth further.
Does it have to be one long stay?
No. For many people the three-plus months is a sequence: residential, then PHP, then IOP, then weekly counseling. NIDA recommends staying in care well beyond 90 days to hold on to the gains.1
The weak point is the gap between steps. Tolerance drops after any stretch without opioids, so using the old amount can be fatal; keep naloxone at home.2
Who decides how long your loved one stays?
The clinical team and the insurance plan, and they decide separately. The team should review the treatment plan often and change it as needs change,1 so ask how they measure progress.
The plan decides what it will pay for. For residential care and PHP, it may approve a few days at a time and review progress before approving more. Our page on how insurers approve treatment explains how that review works.
Those limits are covered by federal parity law. Most private plans that cover addiction treatment can’t restrict it more tightly than comparable medical care, whether through day limits or rules like prior authorization.6 The 2008 law and its 2013 rules still apply. In May 2025, federal agencies said they would not enforce the new parts of a 2024 parity rule until a court challenge is decided, plus 18 months.7 Rules vary by plan type, and if days are denied you can appeal and use your parity rights.
What if care ends sooner than expected?
Care is ending sooner than planned. What now?
InteractiveWhy is care ending?
See possible outcomes
- Ask the clinical team, then ask about appeals A denial is a payment decision, not proof your loved one is ready. If the team thinks more care is needed, ask the program’s doctor to request a call with the plan’s reviewer (a peer-to-peer review). Get the denial in writing and ask about an urgent appeal.
- Keep the door open Ask the program to book an outpatient or IOP appointment they’ll actually go to. If they use opioids, ask about starting buprenorphine or methadone before they leave. Tell your loved one you’re glad for the days they stayed and that coming back is an option.
- Make the next step concrete Before discharge, get the next program’s start date, address and schedule in writing, plus medication refills and a named contact there.
What should we ask a program about length of stay?
Questions about length of stay
Frequently asked questions
Can my loved one leave rehab early?
If they went in voluntarily, usually yes, and many people do.1 Rules for court-ordered or involuntary treatment vary by state.
Does a relapse mean treatment was too short?
Not necessarily. Recovery often takes more than one round of treatment, and a return to use is a reason to restart or adjust care rather than proof it failed.1
How long do people stay on methadone or buprenorphine?
Will a longer stay cost more?
Usually. What you owe depends on the services billed, the days your plan approves, your deductible and your coinsurance. Our guide to what rehab really costs walks through the math.
Sources
- NIDA — Principles of Drug Addiction Treatment: A Research-Based Guide (3rd edition). nida.nih.gov/sites/default/files/podat-3rdEd-508.pdf — accessed Oct 2026
- U.S. Department of Justice, Bureau of Justice Assistance and National Institute of Corrections with ASAM — Guidelines for Managing Substance Withdrawal in Jails (June 2023). asam.org/docs/default-source/guidelines/guidelines_for_managing_substa… — accessed Oct 2026
- American Society of Addiction Medicine — The ASAM Clinical Practice Guideline on Alcohol Withdrawal Management (2020). asam.org/docs/default-source/quality-science/the_asam_clinical_practic… — accessed Oct 2026
- Medicare.gov — Mental Health Care (Outpatient): Intensive Outpatient Program Services. medicare.gov/coverage/mental-health-care-outpatient-intensive-outpatie… — accessed Oct 2026
- Medicare.gov — Mental Health Care (Outpatient): Partial Hospitalization. medicare.gov/coverage/mental-health-care-outpatient-partial-hospitaliz… — accessed Oct 2026
- Centers for Medicare & Medicaid Services — The Mental Health Parity and Addiction Equity Act (MHPAEA). cms.gov/marketplace/private-health-insurance/mental-health-parity-addi… — accessed Oct 2026
- U.S. Departments of Labor, HHS and the Treasury — Statement regarding enforcement of the final rule on requirements related to the Mental Health Parity and Addiction Equity Act (May 15, 2025). cms.gov/files/document/statement-regarding-enforcement-final-rule-requ… — accessed Oct 2026
- CMS — State Medicaid Director Letter #17-003: Strategies to Address the Opioid Epidemic (2017). medicaid.gov/federal-policy-guidance/downloads/smd17003.pdf — accessed Oct 2026
- SAMHSA — Methadone (updated December 2025). samhsa.gov/substance-use/treatment/options/methadone — accessed Oct 2026