This in-depth guide explains how to use UnitedHealthcare insurance to access drug and alcohol rehab on Long Island, focusing on Nassau and Suffolk County. It covers typical UHC benefits for detox, inpatient, PHP, IOP, outpatient, and medication-assisted treatment, and shows readers how to verify coverage, understand deductibles and copays, and choose reputable, evidence-based providers. The article also links to trusted resources such as OASAS, SAMHSA, NIH, NIDA, and local Long Island treatment resources, and encourages readers to call (631) 888-6282 for a confidential benefits check and help finding UnitedHealthcare-covered rehab.