Most inpatient rehab programs last between 30 and 90 days, with 30-day programs being the most common starting point. The actual length of your stay depends on the substance involved, the severity of the addiction, whether you’re also dealing with a mental health condition, and how you respond to treatment. Some people complete a shorter program and transition to outpatient care, while others benefit from stays that extend well beyond 90 days.
Standard Program Lengths
Inpatient rehab programs generally fall into two categories. Short-term programs run 30 to 45 days, while long-term programs span 90 days or more. A large study of nearly 16,000 veterans in residential substance use treatment found that stays between 35 and 49 days hit a practical sweet spot, balancing treatment outcomes against the point where additional days start yielding diminishing returns. That said, the research overall is mixed, with some studies supporting roughly 30 days and others arguing that at least 90 days produces better long-term results.
Short-term programs tend to work best for people with a shorter history of substance use, a strong support system waiting at home, or those re-entering treatment after a relapse. They’re also a reasonable starting point if you’re unsure about committing to a longer stay. Long-term programs of 90 days or more are typically recommended for people dealing with chronic or severe addiction, multiple relapses, co-occurring mental health disorders, or an unstable home environment.
What Happens During Detox
The first phase of inpatient rehab is medically supervised detox, which clears the substance from your body before therapeutic work begins. How long detox takes depends heavily on the substance. For alcohol, withdrawal symptoms typically start within 6 to 24 hours after the last drink, peak between 24 and 72 hours, and then begin to ease. Most people move through the acute phase within a week, though some experience lingering symptoms like insomnia and mood changes that can persist for weeks or months.
Opioid withdrawal follows a similar general arc, with acute symptoms usually peaking within the first few days and resolving within one to two weeks. Benzodiazepine withdrawal can take considerably longer, sometimes stretching over several weeks of medical supervision. Detox alone isn’t considered treatment. It’s the stabilization step that makes the therapeutic portion of rehab possible. You stay in detox until you’re physically and psychologically stable enough to engage in counseling and group work.
How Treatment Is Structured
Once detox is complete, the core of inpatient rehab involves a structured daily schedule of individual therapy, group therapy, and additional approaches like experiential therapy, art therapy, mindfulness practice, or other modalities depending on the facility. You live on campus for the duration, which removes you from the environment and triggers associated with substance use.
Treatment follows a general progression through several milestones: stabilization, engagement with the therapeutic process, goal setting, achieving remission from the substance use disorder, and building the supports needed to maintain that remission after discharge. These milestones matter more than the calendar. Modern clinical guidelines, including the widely used ASAM Criteria, emphasize that patients should move through levels of care based on their actual progress rather than arbitrary predetermined time frames. Your treatment team evaluates your biological, psychological, social, and cultural circumstances to decide when you’re ready for the next step.
When Mental Health Conditions Are Involved
If you’re dealing with depression, anxiety, PTSD, or another mental health condition alongside addiction, treatment typically takes longer. Hospital data from the Agency for Healthcare Research and Quality shows that stays involving a co-occurring mental or substance use disorder averaged 5.4 days compared to 4.2 days for stays without one. While those numbers reflect general hospital admissions rather than residential rehab specifically, the pattern holds: treating two conditions simultaneously requires more time and more intensive resources.
In residential rehab, a dual diagnosis often means your treatment plan includes psychiatric evaluation, medication management, and therapy that addresses both conditions together rather than in isolation. This integrated approach is more effective than treating addiction and mental health separately, but it adds complexity that can extend your stay into the 60- to 90-day range or beyond.
What Determines When You’re Discharged
Discharge decisions are based on clinical milestones, not simply on counting days. You’re generally considered ready for discharge when you’ve accomplished the goals laid out in your treatment plan, achieved stabilization, met remission criteria for the substance use disorder, and built enough external support to maintain your recovery outside the facility. That support might include a sober living arrangement, outpatient therapy appointments, a recovery community, or a combination of all three.
Insurance also plays a role. Many insurance plans authorize a specific number of days and then require clinical justification for extensions. Treatment teams regularly submit progress updates to demonstrate ongoing medical necessity, and stays can be extended or shortened based on these reviews. If your insurance covers 30 days but your clinical team believes you need 60, they’ll advocate for continued coverage, though approval isn’t guaranteed.
What Comes After Inpatient Rehab
Inpatient rehab is one piece of a longer continuum of care. Most people step down into a less intensive level of treatment rather than returning directly to normal life. Partial hospitalization programs (PHP) involve attending treatment sessions during the day while living at home or in a sober living house. Intensive outpatient programs (IOP) require fewer hours per week and allow you to work or attend school part-time. Transitional or sober living provides a structured but less restrictive environment to practice the skills learned in rehab before fully reintegrating.
The total time spent in some combination of these levels of care often stretches to several months, even if the inpatient portion was only 30 days. The residential stay addresses the acute phase of treatment, but the months of outpatient care and aftercare that follow are where long-term recovery habits take root.