What significant legislation governs public drinking water supplies in the United States?

The Safe Drinking Water Act (SDWA) is the significant legislation that specifically governs public drinking water supplies in the United States. Enacted in 1974 and amended several times since, the SDWA is focused on ensuring the quality of Americans' drinking water by establishing minimum health standards for drinking water to protect against both natural and man-made contaminants.

Under the SDWA, the Environmental Protection Agency (EPA) has the authority to set and enforce standards for drinking water quality and oversees states, localities, and water suppliers to ensure compliance. This act plays a critical role in safeguarding public health by regulating the sources of drinking water and ensuring that the water supplied to consumers meets stringent safety standards.

The Clean Water Act, while also important, primarily addresses water pollution and the quality of water bodies such as rivers and lakes, rather than the direct quality of drinking water. The Water Resources Development Act focuses on water resource management projects, and the Ocean Dumping Ban Act pertains primarily to the disposal of waste into oceans, rather than drinking water supplies. Therefore, the focus of the SDWA on public drinking water makes it the correct answer for this question.