The law that specifically regulates discharges of pollutants into US waters and establishes water quality standards for surface waters is the Clean Water Act (CWA). The CWA aims to restore and maintain the integrity of the nation's waters by preventing point and nonpoint source pollution and by setting water quality standards.
The other options you mentioned serve different purposes:
- The Safe Drinking Water Act focuses on ensuring the quality of Americans' drinking water.
- The Environmental Protection Agency (EPA) is the federal agency responsible for enforcing the Clean Water Act and other environmental laws, but it is not a law itself.
- The National Environmental Policy Act (NEPA) requires federal agencies to assess the environmental impacts of their proposed actions before making decisions, but it does not specifically regulate water quality or discharges into water bodies.
Therefore, the correct answer is the Clean Water Act.