My recent article in Infection Control Today advances a conceptual framework positioning hospital Environmental Services (EVS) as the “immune system” of healthcare facilities, drawing a metaphorical and functional comparison with human biological immunity. Healthcare-associated infections (HAIs) continue to present systemic risks, affecting approximately one in 31 hospitalized patients daily. EVS serves as both the innate and adaptive defense of hospitals, with routine cleaning paralleling broad innate barriers and targeted interventions reflecting adaptive immune responses. Parallels are drawn between EVS surveillance and cytotoxic/helper T cell activity, and between institutional memory, training, and B cell antibody production. Case analyses, including EVS responses during the COVID-19 pandemic, demonstrate adaptive resilience in the face of emergent pathogens. The discussion underscores consequences of EVS dysfunction, likened to immunodeficiency and autoimmunity, and highlights the necessity of strong leadership, training, and interdisciplinary integration. By reframing EVS as a clinical partner, this paper elevates its role in safeguarding institutional health and patient safety.