What type of impact is most often associated with Category 4 SSO?

The most accurate choice regarding the type of impact associated with Category 4 Sanitary Sewer Overflows (SSOs) is that Category 4 SSOs typically do not have surface water impact. Category 4 SSOs are characterized by minor spills that do not reach surface waters and are often related to blockages or equipment failures that occur at facilities or within systems, but do not result in significant overflow volumes.

In this context, these SSOs are generally contained within the collection system or at the point of origin, which means they are less likely to pose immediate threats to the environment or public health in comparison to greater severity categories. This distinction is crucial because it reflects the overall impact of SSOs based on their category, allowing for better assessment and management practices.

Choices implying severe environmental damage or significant public health risks are more relevant to higher severity category SSOs, which can result in adverse environmental effects or pose serious health hazards to the public. Hence, understanding that Category 4 SSOs are associated with no surface water impact reinforces the importance of effective monitoring and management of sewage systems to mitigate potential issues in more severe cases.