Part 1. Background and Regulatory Context

CONTENTS

Regulatory Requirements and Applicable Standards
     MS4s Definitions
     NPDES Permits
     Requirements for Regulated Small MS4s
     Stormwater Management Programs
     Notice of Intent
     Deadlines
Options for Permit Coverage
     Option 1: General Permits
     Option 2: Co-Permittee
     Option 3: Individual Permits

REGULATORY REQUIREMENTS AND APPLICABLE STANDARDS

The Stormwater Phase II Final Rule requires you, the operator of a regulated small municipal separate storm sewer system (MS4), to obtain National Pollutant Discharge Elimination System (NPDES) permit coverage because your stormwater discharges are considered "point sources" of pollution. MS4s are considered point sources because they discharge stormwater into discrete conveyances, including roads with drainage systems and municipal streets. MS4s are publicly owned or operated and are designed or used for collecting or conveying stormwater.

EPA categorizes MS4s as either "small," "medium," or "large." The Phase I Stormwater Rule covers medium and large MS4s. A medium MS4 is an MS4 located in an incorporated place or county with a population of 100,000–249,999 (according to the 1990 Census). A large MS4 is an MS4 located in an incorporated place or county with a population of at least 250,000.

A small MS4 is one that is not already defined as medium or large. The Phase II Stormwater Rule covers a subset of small MS4s that are called "regulated small MS4s." Regulated small MS4s are automatically designated if they are located in "urbanized areas" (as defined by the Bureau of the Census). Other small MS4s located outside urbanized areas may be designated on a case-by-case basis by the NPDES permitting authority. EPA has published two fact sheets that provide more information about designation of regulated small MS4s [PDF - 247 KB - 4 pp] and the definition of urbanized areas [PDF - 263 KB - 3 pp].

NPDES Permits

NPDES stormwater permits are issued by an NPDES permitting authority, which may be a NPDES-authorized State or EPA in non-authorized States. A list of EPA and State stormwater contacts is provided on EPA's web site. Once you submit a permit application and permit coverage is obtained, you must satisfy the conditions of the permit and submit periodic reports on the status and effectiveness of the program at reducing pollutants to the MEP.

As a Phase II regulated small MS4, you are required to submit a permit application and obtain coverage under an NPDES stormwater permit. Under the permit, you will be required to develop and implement a stormwater management program that includes the 6 minimum control measures, evaluation/assessment and reporting efforts, and recordkeeping, as described below. You must design a stormwater management program that:

• Reduces the discharge of pollutants to the "maximum extent practicable" (MEP);
• Protects water quality; and
• Satisfies the appropriate water quality requirements of the Clean Water Act.

MEP is a standard that establishes the level of pollutant reductions that MS4 operators must achieve through implementation of a stormwater management program. The strategies used to reduce pollutants to the MEP may be different for each small MS4 because of unique local hydrologic, geologic, and water quality concerns in different areas. EPA envisions that permittees will determine what the MEP is on a location-by-location basis and consider such factors as conditions of receiving waters, specific local concerns, and other aspects of a comprehensive watershed plan.

Because so many diverse factors can dictate the specifics of a stormwater management program, you should determine appropriate BMPs to satisfy each of the minimum control measures through an evaluative process. The definition of "MEP" should adapt continually to both current conditions and BMP effectiveness, but ultimately, successive iterations of the mix of BMPs and measurable goals should be made to achieve the objective of meeting water quality standards. If, after implementing the minimum control measures, there is still water quality impairment associated with discharges from the MS4, you will need to expand or better tailor your BMPs.

NPDES permitting authorities will review the identified BMPs and measurable goals and determine if they are likely to reduce pollutants to the MEP, protect water quality, and satisfy the appropriate water quality requirements of the Clean Water Act. If the permitting authority does not think that you are reducing pollutants to the MEP, they can request that you revise your mix of BMPs and measurable goals.

The Phase II Rule defines a stormwater management program for a small MS4 as a program composed of six elements that, when implemented together, are expected to reduce pollutants discharged into receiving waterbodies to the MEP. These six program elements, or minimum control measures, are

• Public Education and Outreach on Stormwater Impacts;
• Public Involvement/Participation;
• Illicit Discharge Detection and Elimination;
• Construction Site Runoff Control;
• Post-Construction Stormwater Management in New Development and Redevelopment;
• Pollution Prevention/Good Housekeeping for Municipal Operations.

For each minimum control measure, you will select and implement BMPs and measurable goals that comprehensively address the specific stormwater problems in your area. The process for developing a stormwater management program is described in Part 4 of this guidance, and examples of BMPs and measurable goals are presented in Part 3.

To apply for coverage under a general permit, you must fill out a Notice of Intent (NOI) application form. You will be asked for the following information:

• Best management practices (BMPs) for each of the six minimum control measures;

• Measurable goals for each of the BMPs (i.e., narrative or numeric standards used to gauge program effectiveness);

• A timeline for implementation of each measure (estimate months and years to implement each measure, including interim milestones and frequency); and

• Specify the individual(s) or group(s) responsible for implementing or coordinating the stormwater program.

There are a number of implementation options for regulated small MS4 operators. They include obtaining coverage under a general permit, participating in the implementation of an existing Phase I MS4's stormwater program as a co-permittee (including sharing responsibility for program development with a nearby regulated small MS4), or applying for an individual permit. These options are described in detail below. The deadline for applying for permit coverage is March 10, 2003. Check with your state or EPA regional NPDES permitting authority to learn more about permitting in your area.

Option 1. General Permits

• Once a general permit is issued, submit a Notice of Intent (NOI) application form to the NPDES permitting authority to apply for permit coverage under the general permit conditions.
  
  
• In completing the NOI, you need to include a description of your stormwater management program, including best management practices (BMPs) and measurable goals for each of the 6 minimum control measures.
  
  
• Although general permits have a set of requirements determined by the permitting authority, they still provide the flexibility to develop an individualized stormwater program that addresses the particular characteristics of your water quality problems and the needs of your system.

Other Phase II MS4s:

• Partnering with neighboring Phase II MS4s allows you to capitalize on existing resources in meeting Phase II requirements.
  
  
• This option also provides you the opportunity to forge a link between your stormwater program and a regional or watershed management plan.
  
  
• Check with your State or EPA permitting authority for more information about submitting a joint NOI with one or more small MS4s in your area.

• Partnering with a Phase I (larger) MS4 offers an attractive option for you because you could participate in an existing stormwater management program. This can be accomplished by you and your neighboring MS4 jointly seeking a modification of their Phase I MS4 permit.
  
  
• As a limited Phase I co-permittee, you would be responsible for compliance with the permit's conditions that are applicable to your jurisdiction, which would be the applicable terms of the modified Phase I individual permit rather than the minimum control measures in the Phase II Final Rule.

• You may seek coverage under an individual NPDES permit, which is tailored for an individual MS4.
  
  
• Upon submitting the appropriate application(s), the NPDES permitting authority develops a permit for that particular applicant based on the information submitted.
  
  
• The draft permit is then published for public comment before being finalized and issued.
  
  
• This option may take additional time and involve additional documentation, public notice, and comment than either the general permit or co-permittee options.

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Last updated on October 30, 2007 9:43 AM
URL:http://cfpub2.epa.gov/npdes/stormwater/measurablegoals/part1.cfm