St. Joseph County, IN Environmental Rules: Stormwater Management (2026)

Chapter 53 of the county code implements Indiana's Rule 5 storm water program for every unincorporated parcel and the county's MS4 partnering entities, the Towns of Osceola and Roseland. 02, anyone who does not already hold an individual NPDES permit and who disturbs one acre or more, or less than an acre as part of a larger common plan of development that totals an acre or more, must comply with this chapter. 03 sets the SWPPP mechanics: the plan is submitted in triplicate to the county engineering department, Attn: MS4 Operator, for review, and the MS4 Operator forwards copies to the local soil and water conservation district and any partnering entity for comment.

Every SWPPP must carry a filing fee set by the appendix schedule of fines and fees, and the county has 28 calendar days from receipt to notify the applicant whether the plan is sufficient or deficient; if the county misses that window, the applicant may send the Notice of Intent straight to IDEM. A single SWPPP covers an entire common plan of development, so individual home builders on a residentially zoned subdivision do not each file separately. C. 15-5-2(b) and (c), and utility work under a county utility permit.

03(L). 04 require the permittee to notify the MS4 Operator at least five working days before construction starts each season and to document its own control-measure inspections. The county engineer or MS4 Operator can also require a SWPPP for a commercial, office or industrial site under one acre if it will be at least 80 percent impervious.