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Storm Water Regulations, Permitting, and Related Information

Stormwater Permitting

The Stormwater Program issues permits and monitors compliance for stormwater associated with industrial activity, stormwater associated with construction activity, and stormwater associated with municipal separate storm sewer systems (MS4s).

  • Construction/Land Disturbance Stormwater Permitting (327 IAC 15-5):
    • IDEM administers a general permit program that targets construction activities that result in land disturbance of one acre or more. The construction stormwater permit program is intended to reduce pollutants, principally sediment, that are a result of soil erosion and other activities associated with land-disturbing activities.
    • An option to view projects with permit coverage under the construction stormwater general permit (information, applications and terminations) is available on nSITE Explorer.
    • An option to submit Rule 5 forms online is available through the Regulatory ePortal.
  • Industrial Stormwater Permitting (327 IAC 15-6):
    • IDEM administers a general permit program that targets stormwater run-off associated with industrial activities. Requirements of this rule apply to specific categorical industrial facilities, which are exposed to stormwater.
  • Municipal Separate Storm Sewer Systems:
    • 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 an individual stormwater 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.