Substance use treatment; Detoxification; Outpatient; Outpatient detoxification; Outpatient methadone/buprenorphine or naltrexone treatment; Methadone used in Treatment; Buprenorphine used in Treatment; Does not treat alcohol use disorder; Buprenorphine detoxification; Federally-certified Opioid Treatment Program; Methadone detoxification; Methadone; Buprenorphine with naloxone; Buprenorphine without naloxone; Cognitive behavioral therapy; Motivational interviewing; Relapse prevention; Substance use disorder counseling; Private for-profit organization; State Substance use treatment agency; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); SAMHSA certification for opioid treatment program (OTP); Drug Enforcement Agency (DEA); Medicare; Medicaid; Federal military insurance (e.g., TRICARE); Private health insurance; Cash or self-payment; Adult women; Pregnant/postpartum women; Adult men; Seniors or older adults; Veterans; Clients with co-occurring mental and substance use disorders; Clients with HIV or AIDS; Comprehensive mental health assessment; Comprehensive substance use assessment; Outreach to persons in the community; Complete medical history/physical exam; Screening for substance use; Breathalyzer or blood alcohol testing; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; TB screening; Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Self-help groups; Assistance with obtaining social services; Mentoring/peer support; Employment counseling or training; Opioids detoxification; Medication routinely used during detoxification; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Marital/couples counseling; Smoking permitted in designated area; Adults; Seniors; Young adults; Female; Male; Opioid use disorder clients only; Spanish; Other languages (excluding Spanish); Arabic; Vaping permitted in designated area; Case management service; Domestic violence services, including family or partner; Early intervention for HIV; Mental health services; Social skills development; Transportation assistance