The Storm Water Program manages the permitting of large municipal storm water dischargers, storm water associated with industrial activity, storm water associated with construction activity, and storm water associated with municipal separate storm sewer systems (MS4s).
IDEM administers a general permit program that targets construction activities that result in land disturbance of one acre or more. 327 IAC 15-5 is designed to reduce pollutants, principally sediment, that are a result of soil erosion and other activities associated with land-disturbing activities.
IDEM administers a general permit program that targets storm water runoff associated with industrial activities. Requirements of this rule apply to specific categorical industrial facilities, which are exposed to storm water.
Under Phase I, this general permit rule was not necessary. Phase I applied to areas with a population greater than 100,000. Only the City of Indianapolis met Phase I criteria, and was issued a storm water permit. Under Phase II, MS4 entities (cities, towns, universities, colleges, correctional facilities, hospitals, conservancy districts, homeowner's associations and military bases) located within urbanized areas, as delineated by the U.S. Census Bureau, or, for those MS4 areas outside of urbanized areas, serving a population greater than 7,000 are regulated.