Nonpoint source water quality refers to water pollution that

• A. Water pollution from a single, identifiable source
• B. Water pollution that does not originate from a single, identifiable source, often linked to agricultural runoff
• C. Water quality issues caused only by urban runoff
• D. Groundwater contamination from natural sources

Answer: (B)

Nonpoint source pollution describes water contamination that comes from many diffuse sources rather than a single identifiable outlet. It happens when rainfall or irrigation runs across lands—like agricultural fields, pastures, construction sites, and urban surfaces—and picks up nutrients, sediments, and chemicals, carrying them into streams, lakes, and groundwater. Because there isn’t one obvious discharge point to pinpoint, this type of pollution is harder to trace and regulate.

That makes the best answer the one that says pollution does not originate from a single, identifiable source and is often linked to agricultural runoff. The other options point to a single source (point source), or to too narrow or unrelated scenarios (urban runoff only, groundwater from natural sources), which don’t capture the diffuse, cumulative nature of nonpoint source pollution.