Which US environmental law requires an Environmental Impact Statement to be prepared?

The National Environmental Policy Act (NEPA) is the legislation that mandates the preparation of Environmental Impact Statements (EIS) for projects involving federal funding or permits. This law establishes a national policy for the environment and ensures that all branches of government consider the environment before undertaking any major federal action that significantly affects the quality of the human environment.

The requirement for an EIS includes detailed examination of the effects of proposed actions on the environment, alternatives to the proposed action, and the potential mitigation of adverse impacts. This process promotes transparency and public involvement in governmental decision-making related to environmental issues. The law is a cornerstone of federal environmental policy in the U.S. and established the framework for environmental review that is utilized in various sectors.

While the other laws listed have important functions regarding water quality, species protection, and safe drinking water, they do not specifically mandate the preparation of Environmental Impact Statements like NEPA does.