What is the maximum population size defined in Phase 2 regulations?

The correct answer is defined as fewer than 100,000 people. This threshold is significant in the context of Phase 2 of the National Pollutant Discharge Elimination System (NPDES) regulations under the Clean Water Act, which focuses on the management of stormwater discharges from small municipal separate storm sewer systems (MS4s).

Phase 2 regulations specifically apply to medium and small communities, particularly those serving populations of less than 100,000. Establishing this population cutoff is crucial because it influences the implementation of stormwater management practices, aiming to reduce pollutants in stormwater runoff and improve overall water quality. Communities below this population threshold are required to develop and implement a Stormwater Management Program (SWMP) which includes various components such as public education, involvement, and good housekeeping practices to manage stormwater effectively.

Understanding this population criteria is essential for compliance with environmental regulations and for communities to understand their responsibilities concerning stormwater management as regulated by the Environmental Protection Agency (EPA).