Storm Water Management

Phase II Regulations

Ohio EPA MS4 Phase II Website Storm Water BMPs (USEPA website)
Phase II affected jurisdictions  

Background

Storm water discharges are generated by runoff from paved surfaces including streets, parking lots, and other impervious areas (e.g., buildings) during rainfall and snow events. Storm water runoff often contain pollutants such as oil, sediment, or chemicals in quantities that could adversely affect water quality. Most storm water discharges are considered point sources by EPA and therefore require coverage by an National Pollutant Discharge Elimination System (NPDES) permit. According to EPA, a biennial summary of State surveys of US water quality, indicate 40 percent of surveyed US waterbodies are still impaired by pollution and do not meet water quality standards. Polluted storm water runoff is a leading cause of this impairment. The primary method to control storm water discharges is through the use of best management practices.

Phase I of the USEPA storm water program regulated storm water runoff from: medium and large municipal separate storm sewer systems (MS4s) serving populations of 100,000 or greater; construction activities disturbing 5 acres of land or greater; and ten categories of industrial activity.

Phase II is intended to further reduce adverse impacts to water quality by instituting controls on the unregulated sources of storm water discharges that have the greatest likelihood of causing environmental degradation. The Ohio EPA Phase II prgram will regulates those small MS4s located in Urbanized Areas of Ohio.

In November 2004 MVRPC released the final Stormwater Model Ordinance (PDF:519 kb) to assist local jurisdictions in managing stormwater and comply with Phase 2 Stormwater regulations. This model approaches both storm water quanity and quality issues. We encourage local jurisdictions to adjust the model to fit their own regulatory frameworks and needs.