Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; Intensive outpatient treatment; Outpatient methadone/buprenorphine or naltrexone treatment; Methadone used in Treatment; Does not use medication assisted treatment for alcohol use disorder; Federally-certified Opioid Treatment Program; Methadone maintenance; Methadone; Medications for HIV treatment; Medications for Hepatitis C treatment; Medication for mental disorders; Private non-profit organization; State Substance use treatment agency; Commission on Accreditation of Rehabilitation Facilities (CARF); Federal, or any government funding for substance use treatment programs; Medicaid; Cash or self-payment; State-financed health insurance plan other than Medicaid; Payment assistance (check with facility for details); Sliding fee scale (fee is based on income and other factors); Clients with co-occurring mental and substance use disorders; Comprehensive mental health assessment; Comprehensive substance use assessment; Interim services for clients; Screening for tobacco use; Screening for substance use; Screening for mental disorders; Breathalyzer or blood alcohol testing; Drug and alcohol oral fluid testing; Drug or alcohol urine screening; HIV testing; STD testing; TB screening; Testing for Hepatitis B (HBV); Testing for Hepatitis C (HCV); Aftercare/continuing care; Discharge Planning; Naloxone and overdose education; Outcome follow-up after discharge; Self-help groups; Housing services; Assistance with obtaining social services; Mentoring/peer support; Employment counseling or training; Treatment for gambling disorder; HIV or AIDS education, counseling, or support; Hepatitis education, counseling, or support; Health education services other than HIV/AIDS or hepatitis; Substance use disorder education; Smoking/vaping/tobacco cessation counseling; Individual counseling; Group counseling; Family counseling; Smoking permitted in designated area; Adults; Young adults; Female; Male; Opioid use disorder clients only; Case management service; Early intervention for HIV; Mental health services; Social skills development; Transportation assistance; Integrated primary care services