What is nonpoint-source pollution?

Nonpoint-source pollution refers to contamination that originates from a broad, diffuse area rather than a single, identifiable source. This type of pollution is often the result of rainfall or snowmelt moving over and through the ground, picking up pollutants along the way and carrying them into bodies of water, such as rivers, lakes, and oceans. The widespread nature of this pollution can make it more challenging to regulate and manage since it cannot be traced back to a specific origin.

For example, when rainwater runs off agricultural fields, urban areas, and construction sites, it can gather fertilizers, pesticides, and debris, leading to water quality issues in surrounding ecosystems. Nonpoint-source pollution is a significant contributor to the degradation of water quality, particularly in developed and agricultural landscapes where land use practices can vary widely.

In contrast, pollution from a single identifiable source, such as a factory or sewage treatment plant, would fall under point-source pollution. The other options, including pollution from a confined area and chemical runoff specifically attributed to household gardens, do not capture the broad and diffuse nature characteristic of nonpoint-source pollution.