MS4 Program

Background

	What is a Municipal Separate Storm Sewer System (MS4)? A conveyance or system of conveyances (including roads, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): Owned or operated by a public body Designed and used for collecting storm water Is not a combined sewer Is not part of a Publically Owned Treatment Works (POTW)

The U.S. EPA's storm water program addressed storm water runoff in two phases. Phase I addressed storm water runoff from large and medium MS4s. Large municipalities with a separate storm sewer system serving a population greater than 250,000 and medium municipalities with a service population between 100,000 and 250,000 had to obtain NPDES permits. Initial application deadlines for large and medium municipalities were November 16, 1992 and May 17, 1993, respectively. As part of their individual NPDES permit applications, the large and medium MS4s had to develop a storm water management program (SWMP).

Individual MS4 permits for discharge of storm water

• City of Dayton [PDF 1,733K]
• City of Toledo [PDF 205K]
• City of Akron [PDF 355K]
• City of Columbus [PDF 286K]

The Phase II regulations address storm water runoff of MS4s serving populations less than 100,000, called small MS4s. More particularly, small MS4s located partially or fully within urbanized areas (UAs), as determined by the U.S. Bureau of the Census, and also on a case-by-case basis for those small MS4s located outside of UAs that Ohio EPA designates into the program. Automatically designated Small MS4s, those in UAs, were required to apply for permit coverage and develop and submit a SWMP by March 10, 2003.

Small MS4 (Phase II) Program Overview

Urbanized Areas

U.S. EPA developed a Fact Sheet [PDF 239K] explaining how urbanized areas affect water quality through increased runoff and pollutant loads and what homeowners can do to prevent storm water pollution.

Ohio EPA developed two general permits that were issued to Phase II Small MS4 communities under the first generation permitting in 2003. The Baseline General Permit allowed a full 5 years for SWMP development/implementation; whereas, the Alternative General Permit for MS4s Located within Rapidly Developing Watersheds required development/implementation of the Construction and Post-Construction minimum control measures within 3 years. The alternative general permit was issued to a select group of MS4s that Ohio EPA considered being located within rapidly developing watersheds. All MS4s will now be covered under the general permit renewal that was issued on January 31, 2009

Regulated Small MS4s

• NPDES Storm Water General Permit List

Small MS4 Informational Materials

• Ohio EPA MS4 Workshops
• USEPA Storm Water Phase II Fact Sheets 
• USEPA National Menu of Best Management Practices
• USEPA Measurable Goals Guidance for Phase II Small MS4s
• USEPA Storm Water Phase II Compliance Assistance Guide [PDF 1,466K]
• OEPA Guidance Brochure for Phase II Small Municipal Separate Storm Sewer System (MS4) Operators [PDF 95K]
• USEPA Storm Water Case Studies
• USEPA Nonpoint Source Outreach Toolbox

Permit Compliance Materials

• MS4 General Permit
• Ohio Storm Water Rules
• Example Model Ordinances
  • Chagrin River Watershed Partners, Inc. [PDF 91K]
  • Stormwater Manager's Resource Center (see Ordinance)
  • Northeast Ohio Areawide Coordinating Agency
• USEPA Educational Outreach Materials
• Illicit Discharge Detection And Elimination Manual by New England Interstate Water Pollution Control Commission [PDF 496K]
• MS4 Program Evaluation Guidance Document
• Illicit Discharge Detection and Elimination Program Manual - A Guidance Manual for the State of Ohio
• Chagrin River Watershed Partners, Inc. (CRWP) has developed a model agreement that a municipality may use to ensure the long-term operation and maintenance of post-construction best management practices (BMPs). This language may need to be modified to reflect local requirements and should be reviewed by the municipality's legal council. The link below will redirect you from Ohio EPA to CRWP's website.
  • CRWP Model Long-Term Post-Construction BMP Maintenance Agreement [PDF]

Potential Funding Sources

• Ohio Environmental Education Fund
• Ohio Water Pollution Control Loan Fund Fact Sheet [PDF 22K]
• Storm Water Utility Information
  • Stormwater Manager's Resource Center (see Program Resources)
  • An Internet Guide to Financing Stormwater Management
  • Guidance For Municipal Stormwater Funding [PDF]
• Catalog of Federal Funding Sources for Watershed Protection

For Additional Information:

See the Storm Water Program Contacts page.

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