v>EPA
United States
Environmental Protection
Agency
Office of Water EPA 833-F-00-013
(4203) January 2000 (revised December 2005)
Fact Sheet 3.0
Storm water Phase II
Final Rule
Stormwater Phase II
Final Rule
Fact Sheet Series
Overview
1.0-Stormwater Phase 11
Proposed 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 Construction Program
Overview
The 1972 amendments to the Federal Water Pollution Control Act, later referred to as the
Clean Water Act (CWA), prohibit the discharge of any pollutant to navigable waters of the
United States from a point source unless the discharge is authorized by a National Pollutant
Discharge Elimination System (NPDES) permit. Efforts to improve water quality under the
NPDES program traditionally have focused on reducing pollutants in industrial process
wastewater and municipal sewage treatment plant discharges. Over time, it has become evident
that more diffuse sources of water pollution, such as Stormwater runoff from construction sites,
are also significant contributors to water quality problems.
Sediment runoff rates from construction sites are typically 10 to 20 times greater than those from
agricultural lands, and 1,000 to 2,000 times greater than those of forest lands. During a short
period of time, construction activity can contribute more sediment to streams than can be
deposited over several decades, causing physical and biological harm to our Nation's waters.
In 1990, EPA promulgated rules establishing Phase I of the NPDES Stormwater program. Phase
I addresses, among other discharges, discharges from large construction activities disturbing 5
acres or more of land. Phase II of the NPDES Stormwater program covers small construction
activities disturbing between 1 and 5 acres. Phase II became final on December 8, 1999 and
small construction permit applications were due by March 10, 2003 (specific compliance dates
will be set by the NPDES permitting authority in each State). This fact sheet outlines the
construction activities covered by Phase I and Phase II, including possible waiver options from
Phase II coverage, and the Phase II construction program requirements.
Who Is Covered Under the Phase I Rule?
Sites Five Acres and Greater
The Phase I NPDES Stormwater rule identifies eleven categories of industrial activity in the
definition of "Stormwater discharges associated with industrial activity" that must obtain an
NPDES permit. Category (x) of this definition is construction activity, commonly referred to
as "large" construction activity. Under category (x), the Phase I rule requires all operators of
construction activity disturbing 5 acres or greater of land to apply for an NPDES Stormwater
permit. Operators of sites disturbing less than 5 acres are also required to obtain a permit if their
activity is part of a "larger common plan of development or sale" with a planned disturbance of
5 acres or greater. "Disturbance" refers to exposed soil resulting from activities such as
clearing, grading, and excavating. Construction activities can include road building,
construction of residential houses, office buildings, industrial sites, or demolition.
What Is Meant by a "Larger Common Plan of Development or Sale"?
As defined in EPA's NPDES Stormwater general permit for construction activity, a "larger
common plan of development or sale" means a contiguous area where multiple separate and
distinct construction activities are occurring under one plan (e.g., the operator is building on
three half-acre lots in a 6-acre development). The "plan" in a common plan of development or
sale is broadly defined as any announcement or piece of documentation
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Fact Sheet 3.0 - Construction Program Overview
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(including a sign, public notice or hearing, sales pitch,
advertisement, drawing, permit application, zoning request,
computer design, etc.) or physical demarcation (including
boundary signs, lot stakes, surveyor markings, etc.) indicating
that construction activities may occur on a specific plot.
What Is the Definition of an "Operator" of a
Construction Site?
As defined in EPA's stormwater general permit for
construction activity, an "operator" is the party or parties
that has:
Q Operational control of construction project plans
and specifications, including the ability to make
modifications to those plans and specifications; or
Q Day-to-day operational control of those activities
that are necessary to ensure compliance with a
stormwater pollution prevention plan (SWPPP) for
the site or other permit conditions (e.g., they are
authorized to direct workers at a site to carry out
activities required by the SWPPP or comply with
other permit conditions).
There may be more than one party at a site performing the
tasks related to "operational control" as defined above.
Depending on the site and the relationship between the parties
(e.g., owner, developer, contractor), there can either be a
single party acting as site operator and consequently be
responsible for obtaining permit coverage, or there can be two
or more operators, all obligated to seek permit coverage. It is
important to note that NPDES-authorized States may use a
different definition of "operator" than the one above.
How Is the Phase II Construction Rule Related
to the Phase I Construction Rule?
In 1992, the Ninth Circuit court remanded for further
proceedings portions of EPA's existing Phase I stormwater
regulation related to the category (x) discharges from large
construction activity (NRDC v. EPA, 966 F.2d at 1292). EPA
responded to the court's decision by designating under
Phase II stormwater discharges from construction activity
disturbing less than 5 acres as sources that should be regulated
to protect water quality. The Phase II Rule designates these
sources as "stormwater discharges associated with small
construction activity," rather than as another category under
"stormwater associated with industrial activity."
Who Is Covered Under the Phase II
Construction Rule?
Sites Between One and Five Acres
The Stormwater Phase II Rule automatically designates, as
small construction activity under the NPDES stormwater
permitting program, all operators of construction site
activities that result in a land disturbance of equal to or
greater than 1 and less than 5 acres.
Sites Less Than One Acre
Site activities disturbing less than 1 acre are also regulated as
small construction activity if they are part of a larger common
plan of development or sale with a planned disturbance of
equal to or greater than 1 acre and less than 5 acres, or if they
are designated by the NPDES permitting authority. The
NPDES permitting authority or EPA Region may designate
construction activities disturbing less than 1 acre based on
the potential for contribution to a violation of a water quality
standard or for significant contribution of pollutants to waters
of the United States.
Are Waivers Available for Operators of
Regulated Construction Activity?
Yes, but only for small, not large, construction activity.
Under the Phase II Rule, NPDES permitting authorities
have the option of providing a waiver from the requirements
to operators of small construction activity who certify to
either one of two conditions:
O Low predicted rainfall potential (i.e., activity occurs
during a negligible rainfall period), where the rainfall
erosivity factor ("R" in the Revised Universal Soil
Loss Equation [RUSLE]) is less than 5 during the
period of construction activity (See Fact Sheet 3.1);
or
© A determination that stormwater controls are not
necessary based on either:
(A) A "total maximum daily load" (TMDL) that
address the pollutant(s) of concern for
construction activities; OR
(B) An equivalent analysis that determines
allocations are not needed to protect water
quality based on consideration of instream
concentrations, expected growth in pollutant
concentrations from all sources, and a margin
of safety.
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Fact Sheet 3.0 - Construction Program Overview
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Pollutants of concern include sediment or a
parameter that addresses sediment (such as total
suspended solids, turbidity, or siltation) and any
other pollutant that has been identified as a cause of
impairment of a receiving waterbody.
The intent of the waiver provision is to waive only those sites
that are highly unlikely to have a negative effect on water
quality. Therefore, before applying for a waiver, operators
of small construction activity are encouraged to consider the
potential water quality impacts that may result from their
project and to carefully examine such factors as proximity to
water resources and sensitivity of receiving waters.
a. What is the Rainfall Erosivity Factor in
Waiver Q?
Waiver O uses the Rainfall Erosivity Factor to determine
whether the potential for polluted discharge is low
enough to justify a waiver from the requirements. It is one
of six variables used by the Revised Universal Soil Loss
Equation (RUSLE)—a predictive tool originally used to
measure soil loss from agricultural lands at various times
of the year on a regional basis—to predict soil loss from
construction sites. The Rainfall Erosivity Factor waiver is
time-sensitive and is dependent on when during the year a
construction activity takes place, how long it lasts, and
the expected rainfall and intensity during that time. For
information about the rainfall erosivity waiver, see Fact Sheet
3.1. An erosivity calculator for construction sites is available
at http://ei.tamu.edu.
b. What is a "TMDL " in Waiver @ ?
For impaired waters where technology-based controls
required by NPDES permits are not achieving State water
quality standards, the CWA requires implementation of the
TMDL process. The TMDL process establishes the
maximum amount of pollutants a waterbody can assimilate
before water quality is impaired, then requires that this
maximum level not be exceeded.
A TMDL is done for each pollutant that is found to be
contributing to the impairment of a waterbody or a segment of
a waterbody. To allow a waiver for construction activities, a
TMDL would need to address sediment, or a parameter
that addresses sediment such as total suspended solids,
turbidity, or siltation. Additional TMDLs addressing common
pollutants from construction sites such as nitrogen,
phosphorus, and oil and grease also may be necessary to
ensure water quality protection and allow a waiver from the
NPDES stormwater program.
A TMDL assessment determines the source or sources of a
pollutant of concern, considers the maximum allowable level
of that pollutant for the waterbody, then allocates to each
source or category of sources a set level of the pollutant that it
is allowed to discharge into the waterbody. Allocations to
point sources are called wasteload allocations.
How Would an Operator Qualify for, and Certify
to, Waiver®?
EPA expects that when TMDLs or equivalent analyses
are completed, there may be a determination that certain
classes of sources, such as small construction activity, would
not have to control their contribution of pollutants of
concern to the waterbody in order for the waterbody to be in
attainment with water quality standards (i.e., these sources
were not assigned wasteload allocations). In such a case, to
qualify for waiver ©, the operator of the construction site
would need to certify that its construction activity will take
place, and the stormwater discharges will occur, within the
area covered either by the TMDLs or equivalent analysis. A
certification form would likely be provided by the NPDES
permitting authority for this purpose.
What Does the Phase II Construction Program
Require?
The Phase II Final Rule requires operators of Phase II small
construction sites, nationally, to obtain an NPDES permit
and implement practices to minimize pollutant runoff. It
is important to note that, locally, these same sites also may be
covered by State, Tribal, or local construction runoff control
programs (see Fact Sheets 2.6 and 2.7 for information on the
Phase II small MS4's construction program). For the Phase II
small construction program, EPA has taken an approach
similar to Phase I where the program requirements are not
fully defined in the rule but rather in the NPDES permit
issued by the NPDES permitting authority.
EPA recommended that the NPDES permitting authorities use
their existing Phase I large construction general permits as a
guide to developing their Phase II small construction permits.
In doing so, the Phase II requirements would be similar to the
three general Phase I requirements summarized below.
Q Submission of a Notice of Intent (NOI) that
includes general information and a certification
that the activity will not impact endangered or
threatened species. This certification is unique to
EPA's NOI and is not a requirement of most
NPDES-delegated State's NOIs;
Q The development and implementation of a
Stormwater Pollution Prevention Plan (SWPPP)
with appropriate BMPs to minimize the discharge
of pollutants from the site; and
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Fact Sheet 3.0 - Construction Program Overview
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LJ Submission of a Notice of Termination (NOT)
when final stabilization of the site has been
achieved as defined in the permit or when another
operator has assumed control of the site.
In July 2003, EPA issued a construction general permit that
covers both large and small construction activities. This
permit, supporting information, and guidance can be found at
http://www.epa.gov/npdes/stormwater/cgp.
Can the Permitting Authority Reference a
Qualifying Erosion and Sediment Control
Program in NPDES Construction Permits?
Yes. The Phase II Rule allows the NPDES permitting
authority to include in its NPDES permits for large and
for small construction activity conditions that incorporate by
reference qualifying State, Tribal, or local erosion and
sediment control program requirements. A qualifying
program must include the following requirements:
Q Requirements for construction site operators to
implement appropriate erosion and sediment control
best management practices;
Q Requirements for construction site operators to
control waste such as discarded building materials,
concrete truck washout, chemicals, litter, and
sanitary waste that may cause adverse impacts to
water quality;
l_) Requirements for construction site operators to
develop and implement a stormwater pollution
prevention plan; and
Q Requirements to submit a site plan for review that
incorporates consideration of potential water quality
impacts.
In addition to the four elements above, a qualifying program
for large construction activities must also include any
additional requirements necessary to achieve the applicable
technology-based standards of "Best Available Technology"
(BAT) and "Best Conventional Technology" (BCT) based
on the best professional judgment of the permit writer.
Should a State, Tribal, or local program include one or more,
but not all, of the elements listed above, the permitting
authority can reference the program in the permit, provided it
also lists the missing element(s) as a condition in the permit.
What are Some Recommended BMPs for Small
Construction Sites?
The approach and BMPs used for controlling pollutants in
stormwater discharges from small construction sites may
vary from those used for large sites since their characteristics
can differ in many ways. For example, operators of small
sites may have more limited access to qualified design
personnel and technical information. Also, small sites may
have less space for installing and maintaining certain BMPs.
As is the case with all construction sites, erosion and sediment
control at small construction sites is best accomplished with
proper planning, installation, and maintenance of controls.
The following practices have shown to be efficient, cost
effective, and versatile for small construction site operators to
implement. The practices are divided into two categories:
non-structural and structural.
Q Non-Structural BMPs
Minimizing Disturbance
Preserving Natural Vegetation
Good Housekeeping Practices
Q Structural BMPs
Erosion Controls
• Mulch
Grass
Stockpile Covers
Sediment Controls
Silt Fence
• Inlet Protection
Check Dams
Stabilized Construction Entrances
Sediment Traps
Most erosion and sediment controls require regular
maintenance to operate correctly. Accumulated sediments
should be removed frequently and materials should be
checked periodically for wear. Regular inspections by
qualified personnel, which can allow problem areas to be
addressed, should be performed after major rain events.
The BMPs listed above as well as additional erosion and
sediment control practices for construction activities are
described in detail in the National Menu of BMPs for
Stormwater Phase II, which can be found at
http ://www. epa. gov/npdes/stormwater.
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Fact Sheet 3.0 - Construction Program Overview
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For Additional Information
Contacts
A. 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").
Your local soil conservation district office. They can
provide assistance with RUSLE and other
conservation related issues. A list of conservation
district contacts is available at
http://www.nacdnet.org/resources/cdsonweb.html
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
• Construction General Permit and Fact Sheet (68
FR 45817)
http://www.epa.gov/npdes/stormwater/cgp
• EPA Stormwater Management for Construction
Activities and Best Management Practices :
Developing Pollution Prevention Plans Guidance
• And many others
"^ Construction Industry Compliance Assistance Center:
http ://www. cicacenter. org/
"^ Agricultural Handbook Number 703, Predicting Soil
Erosion by Water: A Guide to Conservation
Planning With the Revised Universal Soil Loss
Equation (RUSLE), Chapter 2, pp. 21-64, January
1997. http://www.epa.gov/npdes/pubs/ruslech2.pdf
"^ Guidance for Water Quality Based Decisions: The
TMDL Process. April 1991. U.S. EPA Office of
Water. EPA 440/4-91 -001.
http ://www. epa. gov/O WO W/tmdl
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