The National Plumbing Code is a set of guidelines and standards designed to ensure safe and efficient plumbing systems in buildings across the United States. It covers various aspects of plumbing, including installation, maintenance, and safety measures to protect public health and the environment. This code is regularly updated to reflect new technologies and practices in the plumbing industry. Local governments often adopt the National Plumbing Code or modify it to suit their specific needs, ensuring that plumbing systems meet safety and performance requirements in different regions.