The "Residential Recovery for Seniors Act" proposes significant amendments to Title XVIII of the Social Security Act, specifically Medicare Part A, to expand coverage for substance use disorder (SUD) treatment. This legislation aims to establish Medicare coverage for various levels of residential SUD services, addressing a critical gap in current benefits for seniors. The bill introduces three distinct categories of covered residential SUD services: clinically managed low-intensity , clinically managed high-intensity , and medically managed residential services. For each category, the bill meticulously defines the types of services included, such as bed and board, clinical services, assessments, treatment planning, and medical social services, while explicitly excluding certain medical or private-duty nursing services. To ensure quality and appropriate care, the legislation outlines detailed requirements for the programs and facilities providing these services. For instance, programs must offer 24-hour structure and support, conduct multidimensional assessments at admission, and provide access to medical professionals for examinations, prescriptions, and medication management. Specifically, clinically managed high-intensity programs must provide 20 or more hours of clinical services weekly, including withdrawal management. Medically managed programs, designed for more acute needs, require 24-hour nursing services, daily medical interventions, and comprehensive assessments by physicians or advanced practice providers within 24 hours of admission. Furthermore, the bill mandates that the individual's initial and continued need for these services be periodically reviewed and reaffirmed based on evidence-based criteria. This review frequency is set at not less than every 30 days for clinically managed services and every 10 days for medically managed services. Finally, the legislation directs the Secretary of Health and Human Services to develop a per diem prospective payment system for these residential SUD services. This payment system is slated for implementation for cost reporting periods beginning on or after October 1, 2026, with initial payments set to cover 100 percent of estimated reasonable costs and subsequent years adjusted by an appropriate increase factor.