MS4 Stormwater

Johnson County MS4 - Stormwater Division 

The Department of Planning and Zoning is the Operator, as identified by the Indiana Department of Environmental Management and the federal Environmental Protection Agency, of unincorporated Johnson County's MS4, or Municipal Separate Storm Sewer System. In that role, we review and inspect construction and post-construction stormwater quality protection plans for residential, commercial and institutional development; we monitor and regularly inspect county-owned and -maintained outfalls; we receive and investigate complaints of illicit discharges, and, where applicable, bring an enforcement action against illicit dischargers; and we promote stormwater-related public education, involvement and outreach activities through involvement with the Johnson County Partnership for Water Quality.

The Storm Water Hotline has been established to address concerns about flooding, erosion, water quality, construction sites and permits. Please contact us at planning@co.johnson.in.us or 317-346-4350 to report any concerns. It is helpful if contact name and information if provide for thorough tracking as issues are reported and resolved.

The Department also requires and reviews stormwater permits for most development in the unincorporated county area. The stormwater permitting process, which exists in lieu of a standard stormwater utility fee assessed to all property owners, ensures that a given property properly and appropriately manages stormwater runoff, and provides for a high quality of cleanliness of stormwater runoff as it eventually enters county rivers and streams.

New Stormwater Management Ordinance and Stormwater Technical Standards Manual adopted 12-19-2022

Johnson County Stormwater Management Ordinance

Johnson County Stormwater Technical Standards Manual 

Helpful Information for construction activity 

Stormwater - Silt Fence detail

Stormwater - Concrete washout detail

Stormwater -Temporary construction ingress/egress pad for two-acres or larger sites

Stormwater -Temporary construction ingress/egress pad for site smaller than two-acres

Stormwater - Inlet protection mats example