Simulating a response to a hypothetical disaster scenario through a tabletop exercise can help prepare water system managers, operators, and emergency preparedness personnel for the real thing. The purpose is not to solve the scenario, but rather to increase understanding and familiarity, develop communications and confidence, and fine-tune emergency plans. This article provides an overview of the basics necessary to conduct a water system incident tabletop exercise including establishing objectives, identifying key participants, and formatting the exercise, and it offers logistical recommendations. The article also includes a sample scenario broken out by hour. Much of the methodology that applies to a water system incident tabletop exercise can be utilized for conducting tabletop exercises for other emergency scenarios, as well.