What is classified as a Category 1 SSO?

A Category 1 Sanitary Sewer Overflow (SSO) is characterized by significant discharges that pose a prominent risk to public health and the environment. Each choice provided highlights a specific scenario that meets the criteria for a Category 1 SSO.

When any volume of wastewater spills onto the ground and reaches surface waters, it can cause immediate harm to aquatic life and drinking water sources, thus categorizing it as a serious environmental concern. Similarly, any volume of sewage that enters a storm drain and cannot be recovered is problematic because it can lead to contamination of stormwater systems and potentially contribute to pollution in nearby bodies of water. Lastly, any spill greater than 1,000 gallons is classified as a Category 1 SSO due to the sheer volume, which increases the likelihood of harmful consequences on the environment and public health.

Since each situation contributes to the definition and understanding of a Category 1 SSO, the correct answer encompasses all these scenarios, confirming them as valid classifications of what constitutes a Category 1 SSO.