vvEPA
United States
Environmental Protection
Agency
Office of Water EPA 833-F-00-002
(4203) January 2000 (revised December 2005)
Fact Sheet 2.0
Storm water Phase II
Final Rule
Stormwater Phase II
Final Rule
Fact Sheet Series
Overview
1.0 - Stormwater Phase II Final
Rule: An Overview
Small MS4 Program
2.0 - Small MS4 Stormwater
Program Overview
2.1 - Who's Covered? Designation
and Waivers of Regulated Small
MS4s
2.2 - Urbanized Areas: Definition
and Description
Minimum Control Measures
2.3-Public Education and
Outreach
2.4-Public Participation/
Involvement
2.5 - Illicit Discharge Detection
and Elimination
2.6 - Construction Site Runoff
Control
2.7 - Post-Construction Runoff
Control
2.8 - Pollution Prevention/Good
Housekeeping
2.9 - Permitting and Reporting:
The Process and Requirements
2.10 - Federal and State-Operated
MS4s: Program Implementation
Construction Program
3.0 - Construction Program
Overview
3.1 - Construction Rainfall
Erosivity Waiver
Industrial "No Exposure"
4.0 - Conditional No Exposure
Exclusion for Industrial Activity
Small MS4 Storm water Program
Overview
Polluted storm water runoff is often transported to municipal separate storm sewer systems
(MS4s) and ultimately discharged into local rivers and streams without treatment. EPA's
Stormwater Phase II Rule establishes an MS4 stormwater management program that is intended
to improve the Nation's waterways by reducing the quantity of pollutants that stormwater picks
up and carries into storm sewer systems during storm events. Common pollutants include oil and
grease from roadways, pesticides from lawns, sediment from construction sites, and carelessly
discarded trash, such as cigarette butts, paper wrappers, and plastic bottles. When deposited into
nearby waterways through MS4 discharges, these pollutants can impair the waterways, thereby
discouraging recreational use of the resource, contaminating drinking water supplies, and
interfering with the habitat for fish, other aquatic organisms, and wildlife.
In 1990, EPA promulgated rules establishing Phase I of the National Pollutant Discharge
Elimination System (NPDES) stormwater program. The Phase I program for MS4s requires
operators of "medium" and "large" MS4s, that is, those that generally serve populations of
100,000 or greater, to implement a stormwater management program as a means to control
polluted discharges from these MS4s. The Stormwater Phase II Rule extends coverage of the
NPDES stormwater program to certain "small" MS4s but takes a slightly different approach to
how the stormwater management program is developed and implemented.
What Is a Phase II Small MS4?
A small MS4 is any MS4 not already covered by the Phase I program as a medium or large
MS4. The Phase II Rule automatically covers on a nationwide basis all small MS4s located
in "urbanized areas" (UAs) as defined by the Bureau of the Census (unless waived by the
NPDES permitting authority), and on a case-by-case basis those small MS4s located outside of
UAs that the NPDES permitting authority designates. For more information on Phase II small
MS4 coverage, see Fact Sheets 2.1 and 2.2.
What Are the Phase II Small MS4 Program Requirements?
/^\perators of regulated small MS4s are required to design their programs to:
Q Reduce the discharge of pollutants to the "maximum extent practicable" (MEP);
Q Protect water quality; and
Q Satisfy the appropriate water quality requirements of the Clean Water Act.
Implementation of the MEP standard will typically require the development and implementation
of BMPs and the achievement of measurable goals to satisfy each of the six minimum control
measures.
The Phase II Rule defines a small MS4 stormwater management program as a program
comprising six elements that, when implemented in concert, are expected to result in significant
reductions of pollutants discharged into receiving waterbodies.
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Fact Sheet 2.0 - An Overview of the Small MS4 Stormwater Program
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The six MS4 program elements, termed "minimum control
measures," are outlined below. For more information on each
of these required control measures, see Fact Sheets 2.3 - 2.8.
© Public Education and Outreach
Distributing educational materials and performing
outreach to inform citizens about the impacts polluted
Stormwater runoff discharges can have on water quality.
© Public Participation I Involvement
Providing opportunities for citizens to participate in
program development and implementation, including
effectively publicizing public hearings and/or
encouraging citizen representatives on a Stormwater
management panel.
© Illicit Discharge Detection and Elimination
Developing and implementing a plan to detect and
eliminate illicit discharges to the storm sewer system
(includes developing a system map and informing the
community about hazards associated with illegal
discharges and improper disposal of waste).
@ Construction Site Runoff Control
Developing, implementing, and enforcing an erosion and
sediment control program for construction activities that
disturb 1 or more acres of land (controls could include
silt fences and temporary Stormwater detention ponds).
© Post-Construction Runoff Control
Developing, implementing, and enforcing a program to
address discharges of post-construction Stormwater
runoff from new development and redevelopment areas.
Applicable controls could include preventative actions
such as protecting sensitive areas (e.g., wetlands) or the
use of structural BMPs such as grassed swales or porous
pavement.
© Pollution Prevention/Good Housekeeping
Developing and implementing a program with the goal of
preventing or reducing pollutant runoff from municipal
operations. The program must include municipal staff
training on pollution prevention measures and techniques
(e.g., regular street sweeping, reduction in the use of
pesticides or street salt, or frequent catch-basin cleaning).
What Information Must the NPDES Permit
Application Include?
The Phase II program for MS4s is designed to accommodate
a general permit approach using a Notice of Intent (NOI)
as the permit application. The operator of a regulated small
MS4 must include in its permit application, or NOI, its chosen
BMPs and measurable goals for each minimum control
measure. To help permittees identify the most appropriate
BMPs for their programs, EPA issued a Menu of BMPs to
serve as guidance. NPDES permitting authorities can modify
the EPA menu or develop their own list. For more information
on application requirements, see Fact Sheet 2.9.
What Are the Implementation Options?
The rule identifies a number of implementation options for
regulated small MS4 operators. These include sharing
responsibility for program development with a nearby
regulated small MS4, taking advantage of existing local or
State programs, or participating in the implementation of an
existing Phase I MS4's Stormwater program as a co-permittee.
These options are intended to promote a regional approach to
Stormwater management coordinated on a watershed basis.
What Kind of Program Evaluation/Assessment Is
Required?
Permittees need to evaluate the effectiveness of their chosen
BMPs to determine whether the BMPs are reducing the
discharge of pollutants from their systems to the "maximum
extent practicable" and to determine if the BMP mix is
satisfying the water quality requirements of the Clean Water
Act. Permittees also are required to assess their progress
in achieving their program's measurable goals. While
monitoring is not required under the rule, the NPDES
permitting authority has the discretion to require monitoring
if deemed necessary. If there is an indication of a need for
improved controls, permittees can revise their mix of BMPs
to create a more effective program. For more information
on program evaluation/assessment, see Fact Sheet 2.9.
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Fact Sheet 2.0 - An Overview of the Small MS4 Stormwater Program
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For Additional Information
Contacts
"^ U.S. EPA Office of Wastewater Management
http://www.epa.gov/npdes/stormwater
Phone: 202-564-9545
"^ Your NPDES Permitting Authority. Most States and
Territories are authorized to administer the NPDES
Program, except the following, for which EPA is the
permitting authority:
Alaska
District of Columbia
Idaho
Massachusetts
New Hampshire
New Mexico
American Samoa
Guam
Johnston Atoll
Midway and Wake Islands
Northern Mariana Islands
Puerto Rico
Trust Territories
"^ A list of names and telephone numbers for each EPA
Region and State is located at http ://www. epa. gov/
npdes/stormwater (click on "Contacts").
Reference Documents
"^ EPA's Stormwater Web Site
http://www.epa.gov/npdes/stormwater
• Stormwater Phase II Final Rule Fact Sheet Series
• Stormwater Phase II Final Rule (64 FR 68722)
• National Menu of Best Management Practices
for Stormwater Phase II
• Measurable Goals Guidance for Phase II Small
MS4s
• Stormwater Case Studies
• And many others
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