Phase II

A small MS4 is any MS4 not already covered by the Phase I program as a medium or large MS4. The Phase II Rule automatically covers on a nationwide basis all small MS4s located in “urbanized areas” (UAs) as defined by the Bureau of the Census (unless waived by the NPDES permitting authority), and on a case by case basis those small MS4s located outside of the UAs that the NPDES permitting authority designates. The City of Clarksburg is designated as a small MS4.