Phase II Background, Highlights and Governance

Phase II Background

In response to the 1987 Amendments to the Clean Water Act, the U.S. Environmental Protection Agency (EPA) developed Phase I of the National Pollutant Discharge Elimination System (NPDES).  Missouri MS4s regulated under Phase I include Kansas City, Independence and Springfield.

The national Phase II Stormwater Rule was published in the Federal Register Dec. 8, 1999.

Phase I regulations address Stormwater runoff in medium and large communities. It also identified 11 industrial categories required to obtain permits (with some exemptions.)  It also addressed statewide land disturbance on five acres or greater.  Phase II regulations expanded the program to include smaller communities and land disturbance on one acre or greater. 

The Missouri Department of Natural Resources administers the federal stormwater regulations through the Missouri Clean Water Law and Code of State Regulations under the guidance of Missouri’s Clean Water Commission.  The department's Water Pollution Control Branch oversees the Phase II program.

Phase II Highlights

Certain Small Communities were exempt under the 1990 Phase I Stormwater regulations and became subject to Phase II regulations.  These Municipal Separate Storm Sewer Systems (MS4s) were required to obtain a National Pollutant Discharge Elimination System (NPDES) permit by March 10, 2003.  The permit requires these regulated MS4s to have their Stormwater management program in place within five years from date of initial permit issuance.  The program must address six specific minimum control measures.  See Local Government (MS4) Programs for detailed information.

Industrial Classifications Modified There are still 11 categories of industrial classifications covering 30 sectors of industrial activity that are required to obtain Stormwater discharge permits. However, the North American Industry Classification System classifies establishments by their primary type of activity.  In addition, there is now an option for industrial no exposure exemptions. Also, municipally operated industries exempted by theIntermodal Surface Transportation Efficiency Act of 1991, are no longer exempt under Phase II.  See Industrial Permits for detailed information.

Land Disturbance Permits are now required for disturbance of one acre or greater (Phase I affected disturbance of five acres or greater.)  As before, permits must be in place before land disturbance begins at the construction site. This requirement applies statewide.  See Land Disturbance Permits for detailed information.