Which of the following federal laws was established to improve water quality in the United States?

The Safe Drinking Water Act, enacted in 1975, was designed specifically to ensure the quality of Americans' drinking water by setting standards for water quality and overseeing states' implementation of these standards. This legislation focuses on the protection of public health by regulating the nation's public drinking water supply and requiring water suppliers to monitor and report on the quality of the drinking water they provide.

The act establishes maximum contaminant levels for known harmful substances, mandates testing for contaminants, and provides funding for water quality improvement programs. Its purpose is to safeguard drinking water sources, enhancing water quality throughout the U.S. and helping to ensure that water supplies meet health-based standards.

While other laws mentioned, such as the Clean Air Act and the Marine Life Protection Act, address environmental concerns, they do not specifically target the quality of water supplies used for drinking. The Water Sense Act, on the other hand, promotes water efficiency but does not directly regulate water quality. Therefore, the Safe Drinking Water Act is the most pertinent law aimed at improving water quality in the United States.