Data from the Centers for Disease Control and Prevention (CDC) shows improper maintenance of public spas increases risk for Legionnaires' disease. Legionnaires' disease affects thousands of individuals each year and represents a signifcant public health burden, with a 10% case fatality rate and an estimated annual hospitalization cost burden of $433 million.1,2 CDC's Model Aquatic Health Code (MAHC) offers critical guidance for reducing the risk of Legionnaires' disease in public aquatic facilities.