What percentage of the water in the US is covered by the 2015 definition of "waters of the United States"?

The correct answer reflects the fact that the 2015 definition of "waters of the United States" encompasses a broad range of water bodies, significantly expanding the reach of federal jurisdiction under the Clean Water Act. According to the Environmental Protection Agency (EPA) and the Army Corps of Engineers, this definition includes traditional navigable waters, tributaries, and adjacent wetlands, which collectively cover a substantial portion of the water resources in the country.

Specifically, research and assessments indicate that about 60% of the total water in the U.S. falls under this revised definition, meaning the federal government plays a role in regulatory oversight to protect these waters from pollution and adverse development impacts. The expansive nature of this definition aims to protect various ecosystems and prevent degradation of water quality, highlighting the importance of maintaining healthy water resources for environmental and public health.

The remaining options suggest percentages that are less accurate in representing the scope of water categorized under the 2015 rule. Understanding the regulatory landscape surrounding water bodies is crucial for environmental professionals, as it influences land use, conservation efforts, and compliance requirements.