Stormwater and National Pollutant Discharge Elimination System (NPDES) Phase II

Stormwater discharges are generated by runoff from land and impervious areas such as paved streets, parking lots, and building rooftops during rainfall and snow events that often contain pollutants in quantities that could adversely affect water quality. Most stormwater discharges are considered point sources and require coverage by a National Pollutant Discharge Elimination System (NPDES) permit. The primary method to control stormwater discharges is through the use of best management practices (BMPs).

Phases of the NPDES Stormwater Program

Phase I
In 1990, the U.S. Environmental Protection Agency (EPA) developed Phase I of the NPDES Stormwater Program. Under Phase I, EPA required NPDES permit coverage for stormwater discharges from medium and large municipal separate storm sewer systems (MS4s) located in incorporated places or counties with populations of 100,000 or more and construction activity that disturbs five or more acres of land. Operators of the systems, facilities, and construction sites regulated under the Phase I program were required to obtain permits for the stormwater discharge leaving sites.

Phase II
Phase II of the NPDES stormwater program, requires NPDES permit coverage for stormwater discharges from certain regulated small municipal separate storm sewer systems (MS4s); and small construction activities disturbing between 1 and 5 acres of land.

For more information on stormwater management programs, visit the Ohio EPA web site at or the US EPA web site.

Many of the Chagrin River watershed communities were required to submit Phase II stormwater management programs in 2003 to detail how each individual community would comply with the Phase II mandates. The information presented on this page is presented to assist CRWP member communities in compliance with NPDES Phase II regulations.

Links to activities and programs for communities to take credit under their Phase II program.

NPDES Training Courses and Workshops
Please click here for more information.

Municipal Separate Storm Sewer System (MS4) Program Evaluation Guidance
The MS4 Evaluation Guide is primarily for use by NPDES authorities to evaluate the quality of Phase I and Phase II MS4 programs, for permit compliance, technical assistance, and other purposes. It can be used for comprehensive program evaluations, or for certain components. It can also be used by MS4 program managers to evaluate their own programs.

EPA encourages state NPDES stormwater programs to adapt this Guide to their state programs. It is being provided in Word so that programs can incorporate state-specific program components into the Guide, and have a single manual for inspectors and others to use. EPA welcomes feed-back on the Guide based on experiences of state and regional evaluations. As state and EPA NPDES programs conduct more MS4 program evaluations we will undoubtedly learn a number of lessons about program evaluations. We are committed to making timely updates to the guide as the MS4 program evolves (EPA-833-R-07-003).
Document Type: Policy and Guidance Documents
Date Published: 01/01/2007

MS4 Guide with Appendix A
[Click here to view in PDF format - 695KB ]

[Click here to view in WORD format - 781KB ]

Appendices B - D
[Click here to view in PDF format - 588KB ]

[Click here to view in WORD format - 1.1MB ]

Explore the Non Point Source (and Stormwater!)Toolbox:
Toolbox online at www.epa.gov/nps/toolbox this is one of the best multi media resources for every community and it is free.

NPDES Storm Water General Permit List
This page contains lists of entities having National Pollutant Discharge Elimination System (NPDES) Storm Water General Permit Coverage authorization to discharge to surface waters of Ohio. Under each currently effective storm water general permit, dropdown menu options provide the following information:

1. a list of entities covered under the general permit
2. information & guidance pertaining to the general permit
3. the general permit
   Click here for full list

On December 24, 2007, Ohio EPA will be public noticing the following two NPDES draft general permit renewals for public comment:
1)Small MS4 General Permit Renewal.
2)Statewide Construction Storm Water General Permit Renewal.

Both these draft general permits and associated documents can be viewed at the following web page:
http://www.epa.state.oh.us/dsw/storm/index.html
Please comment by February 21, 2008.