Healthy Communities Act of 2018 This bill amends the Public Health Service Act to require the U.S. Preventive Services Task Force to base recommendations regarding the effectiveness, appropriateness, and cost-effectiveness of clinical preventive services on data for the respective populations, including health disparity populations. (Health disparity populations have a significant disparity in the overall rate of disease incidence, prevalence, morbidity, mortality, or survival rates as compared to the general population.)