&EPA
United States
Environmental Protection
Agency
Office of Water EPA 833-F-00-001
(4203) January 2000 (revised December 2005)
Fact Sheet 1.0
Storm water Phase II
Final Rule
An Overview
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
Why Is the Phase II Stormwater Program Necessary?
Cl ince the passage of the Clean Water Act (C WA), the quality of our Nation's waters has
O improved dramatically. Despite this progress, however, degraded waterbodies still exist.
According to the 2000 National Water Quality Inventory (Inventory), a biennial summary of
State surveys of water quality, approximately 40 percent of surveyed U.S. waterbodies are
still impaired by pollution and do not meet water quality standards. A leading source of this
impairment is polluted runoff. In fact, according to the Inventory, 13 percent of impaired
rivers, 18 percent of impaired lake acres and 32 percent of impaired estuaries are affected by
urban/suburban Stormwater runoff.
Phase I of the U.S. Environmental Protection Agency's (EPA) Stormwater program was
promulgated in 1990 under the CWA. Phase I relies on National Pollutant Discharge
Elimination System (NPDES) permit coverage to address Stormwater runoff from:
(1) "medium" and "large" municipal separate storm sewer systems (MS4s) generally serving
populations of 100,000 or greater, (2) construction activity disturbing 5 acres of land or
greater, and (3) ten categories of industrial activity.
The Stormwater Phase II Final Rule is the next step in EPA's effort to preserve, protect,
and improve the Nation's water resources from polluted Stormwater runoff. The Phase II
program expands the Phase I program by requiring additional operators of MS4s in urbanized
areas and operators of small construction sites, through the use of NPDES permits, to
implement programs and practices to control polluted Stormwater runoff. See Fact Sheets 2.0
and 3.0 for overviews of the Phase II programs for MS4s and construction activity.
Phase II is intended to further reduce adverse impacts to water quality and aquatic habitat by
instituting the use of controls on the unregulated sources of Stormwater discharges that have
the greatest likelihood of causing continued environmental degradation. The environmental
problems associated with discharges from MS4s in urbanized areas and discharges resulting
from construction activity are outlined below.
MS4s in Urbanized Areas
Stormwater discharges from MS4s in urbanized areas are a concern because of the high
concentration of pollutants found in these discharges. Concentrated development in
urbanized areas substantially increases impervious surfaces, such as city streets, driveways,
parking lots, and sidewalks, on which pollutants from concentrated human activities settle and
remain until a storm event washes them into nearby storm drains. Common pollutants include
pesticides, fertilizers, oils, salt, litter and other debris, and sediment. Another concern is the
possible illicit connections of sanitary sewers, which can result in fecal conform bacteria
entering the storm sewer system. Stormwater runoff picks up and transports these and other
harmful pollutants then discharges them - untreated - to waterways via storm sewer systems.
When left uncontrolled, these discharges can result in fish kills, the destruction of spawning
and wildlife habitats, a loss in aesthetic value, and contamination of drinking water supplies
and recreational waterways that can threaten public health.
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Fact Sheet 1.0 - Stormwater Phase II Final Rule: An Overview
Page 2
Construction Activity
Uncontrolled runoff from construction sites is a water quality
concern because of the devastating effects that sedimentation
can have on local waterbodies, particularly small streams.
Numerous studies have shown that the amount of sediment
transported by Stormwater runoff from construction sites with
no controls is significantly greater than from sites with
controls. In addition to sediment, construction activities yield
pollutants such as pesticides, petroleum products, construction
chemicals, solvents, asphalts, and acids that can contaminate
Stormwater runoff. During storms, construction sites may be
the source of sediment-laden runoff, which can overwhelm a
small stream channel's capacity, resulting in streambed scour,
streambank erosion, and destruction of near-stream vegetative
cover. Where left uncontrolled, sediment-laden runoff has
been shown to result in the loss of in-stream habitats for fish
and other aquatic species, an increased difficulty in filtering
drinking water, the loss of drinking water reservoir storage
capacity, and negative impacts on the navigational capacity of
waterways.
Are Municipally Operated Sources Exempted
by the Intermodal Surface Transportation
Efficiency Act (ISTEA) of 1991 Affected by
the Final Rule?
Provisions within ISTEA temporarily delayed the deadline
for Phase I industrial activities (with the exception of
power plants, airports, and uncontrolled sanitary landfills)
operated by municipalities with populations of less than
100,000 people to obtain an NPDES Stormwater discharge
permit. Congress delayed the permitting deadline for these
facilities to allow small municipalities additional time to
comply with NPDES requirements. The Phase II Final Rule
ended this temporary exemption from permitting. Since March
10, 2003, all ISTEA-exempted municipally operated
industrial activities were required to obtain permit coverage.
How Was the Phase II Final Rule Developed?
EPA developed the Phase II Final Rule during extensive
consultations with a cross-section of interested
stakeholders brought together on a subcommittee chartered
under the Federal Advisory Committee Act, and with
representatives of small entities participating in an advisory
process mandated under the Small Business Regulatory
Enforcement Fairness Act. In addition, EPA considered
comments submitted by over 500 individuals and
organizations during a 90-day public comment period on
the proposed rule.
Why Does Part of the Phase II Final Rule Use a
Question and Answer Format?
The provisions pertaining to operators of small MS4s are
written in a "readable regulation" form that uses the "plain
language" method. Questions and answers are used to create
more reader-friendly and understandable regulations. The
plain language method uses "must" instead of "shall" to
indicate a requirement and words like "should," "could," or
"encourage" to indicate a recommendation or guidance.
Who Is Covered by the Phase II Final Rule?
The final rule "automatically" covers two classes of
Stormwater dischargers on a nationwide basis:
(1) Operators of small MS4s located in "urbanized
areas" as delineated by the Bureau of the Census. A
"small" MS4 is any MS4 not already covered by
Phase I of the NPDES Stormwater program. See
Fact Sheets 2.1 and 2.2 for more information on
small MS4 coverage.
(2) Operators of small construction activities that
disturb equal to or greater than 1 (one) and less than
5 (five) acres of land. See Fact Sheet 3.0 for more
information on small construction activity coverage.
Waivers
Permitting authorities may waive "automatically designated"
Phase II dischargers if the dischargers meet the necessary
criteria. See Fact Sheets 2.1 (small MS4 waivers overview),
3.0 (construction waivers overview) and 3.1 (construction
rainfall erosivity waiver) for details.
Phased-in Permit Coverage
Permitting authorities may phase-in permit coverage for small
MS4s serving jurisdictions with a population under 10,000 on
a schedule consistent with a State watershed permitting
approach.
Additional Designations by the Permitting Authority
Small MS4s located outside of urbanized areas, construction
activity disturbing less than 1 acre, and any other Stormwater
discharges can be designated for coverage if the NPDES
permitting authority or EPA determines that Stormwater
controls are necessary. See Fact Sheet 2.1 for more
information on the designation of small MS4s located outside
of urbanized areas.
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Fact Sheet 1.0 - Stormwater Phase II Final Rule: An Overview
Page3
What Does the Phase II Final Rule Require?
Operators of Phase II-designated small MS4s and small
construction activity are required to apply for NPDES
permit coverage, most likely under a general rather than
individual permit, and to implement Stormwater discharge
management controls (known as "best management practices"
(BMPs)). Specific requirements for each type of discharge
are listed below.
Small MS4s
A regulated small MS4 operator must develop,
implement, and enforce a Stormwater management
program designed to reduce the discharge of
pollutants from their MS4 to the "maximum extent
practicable," to protect water quality, and to satisfy
the appropriate water quality requirements of the
CWA. The rule assumes the use of narrative, rather
than numeric, effluent limitations requiring
implementation of BMPs.
The small MS4 Stormwater management program
must include the following six minimum control
measures: public education and outreach; public
participation/involvement; illicit discharge detection
and elimination; construction site runoff control;
post-construction runoff control; and pollution
prevention/good housekeeping. See Fact Sheets 2.3
through 2.8 for more information on each measure,
including BMPs and measurable goals.
A regulated small MS4 operator must identify its
selection of BMPs and measurable goals for each
minimum measure in the permit application. The
evaluation and assessment of those chosen BMPs and
measurable goals must be included in periodic
reports to the NPDES permitting authority. See Fact
Sheet 2.9 for more information on permitting and
reporting.
Small Construction Activity
The specific requirements for Stormwater controls on
small construction activity will be defined by the
NPDES permitting authority on a State-by-State
basis.
Many NPDES permitting authorities have adapted
their existing Phase I general permits for large
construction activity to also include small
construction activity. Where this has occurred, a
Stormwater pollution prevention plan is required for
small construction activity. See Fact Sheet 3.0 for
more information on potential program requirements
and appropriate BMPs for small construction activity.
What Is the Phase II Program Approach?
T
Encourages the use of general permits;
I he Phase II program, based on the use of federally
enforceable NPDES permits:
Q Provides flexibility for regulated operators to
determine the most appropriate Stormwater controls;
Q Allows for the recognition and inclusion of existing
NPDES and non-NPDES Stormwater programs in
Phase II permits;
Q Includes public education and participation efforts
as primary elements of the small MS4 program;
Q Attempts to facilitate and promote watershed
planning and to implement the Stormwater program
on a watershed basis; and
Q Works toward a unified and comprehensive NPDES
Stormwater program with Phase I of the program.
How Does the Phase II Final Rule Address the
Phase I Industrial "No Exposure" Provision?
In addition to establishing a deadline for ISTEA facilities
and designating two new classes of dischargers, the
Phase II Final Rule revises the "no exposure" provision
originally included in the 1990 regulations for Phase I of the
NPDES Stormwater program. The provision was remanded to
EPA for further rulemaking and, subsequently, included in its
revised form in the Phase II rule.
Under the Phase II Final Rule, a conditional no exposure
exclusion is available to operators of all categories of Phase I
regulated industrial activity (except category (x) construction
activity) who can certify that all industrial materials and
activities are protected by a storm resistant shelter to prevent
exposure to rain, snow, snowmelt, and/or runoff. To obtain
the no exposure exclusion, written certification must be
submitted to the NPDES permitting authority. The final rule
includes a No Exposure Certification form for use only by
operators of industrial activity in areas where EPA is the
NPDES permitting authority. See Fact Sheet 4.0 for more
information on the conditional no exposure exclusion for
industrial activity.
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Fact Sheet 1.0 - Stormwater Phase II Final Rule: An Overview
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What Resources are Available for Phase II
Communities?
EPA is committed to providing tools to facilitate
implementation of the final Phase II stormwater program
in an effective and cost-efficient manner. The stormwater
Web site includes fact sheets, case studies, guidance
documents, the National Menu of BMPs, and the Measurable
Goals Guidance, as well as other compliance assistance
information. This information can be accessed at EPA's
stormwater Web site at www.epa.gov/npdes/stormwater.
What Is the Schedule for the Phase II Rule?
Q The Phase II Final Rule was published in the Federal
Register on December 8, 1999 (64 FR 68722).
Q The Conditional No Exposure Exclusion option is
available in States where EPA is the permitting
authority (see http://www.epa.gov/npdes/authorization').
Q The NPDES permitting authorities were required to
issue general permits for Phase II-designated small
MS4s and small construction activity by December 9,
2002.
Q Operators of Phase II "automatically" designated
regulated small MS4s and small construction activity
were required to obtain permit coverage within 90 days
of permit issuance.
Q The NPDES permitting authority may phase-in
coverage for small MS4s serving jurisdictions with a
population under 10,000 on a schedule consistent with
a State watershed permitting approach.
Q Operators of regulated small MS4s must fully
implement their stormwater management programs
by the end of the first permit term, typically a 5-year
period.
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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