Drinking water treatment is essential to obtain a healthy source of water that can be distributed throughout a community. There are various methods to disinfect water, and all have trade-offs regarding public health and the environment. For example, chemical disinfectants that use chlorine can produce disinfection by-products within treated drinking water. The Environmental Protection Agency regulates these disinfection by-products because of their potential to cause cancer. Ultraviolet (UV) light is a physical disinfection method that does not produce these disinfection by-products, which is why it is becoming a preferred method for water treatment. For this research, I conducted a comparative life cycle assessment (LCA) for chemical and physical disinfection methods. The main factors considered within this LCA were energy consumption and human toxicity risk. The results from my research support my original hypothesis that the assessed chemical disinfection method had less energy consumption and a higher human toxicity risk compared to the assessed physical disinfection method. The results show that each method has trade-offs and that this LCA can provide extensive knowledge on which disinfection method would work best for the Bethlehem, New Hampshire community based on the stakeholders’ priorities.