xvEPA
United States
Environmental Protection
Agency
Office of Water
(4203)
EPA833-F-00-013
January 2000
Fact Sheet 3.0
Storm Water Phase II
Final Rule
Storm Water Phase II
Final Rule
Fact Sheet Series
Overview
1.0-Stoim Water Phase II
Proposed Rule: An Overview
Small MS4 Program
2.0- Small MS4 Storm Water
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 - Permuting 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
'T'he 1972 amendments to the Federal Water Pollution Control Act, later referred to as the
JL 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 storm water 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 penod 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 storm water program.
Phase I addresses, among other discharges, discharges from large construction activities
disturbing 5 acres or more of land Phase n of the NPDES storm water program covers small
construction activities disturbing between 1 and 5 acres Phase n became final on December 8,
1999 with small construction permit applications 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 n, including possible waiver options from
Phase n coverage, and the Phase E construction program requirements
Who Is Covered Under the Phase I Rule?
Sites Five Acres and Greater
The Phase I NPDES storm water rule identifies eleven categones of industrial activity in the
definition of "storm water 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 storm water
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"?
A s defined in EPA's NPDES storm water general permit for large construction activity, a
•/"V'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
Pagçj
(including a sign, public notice or heanng, sales pitch,
advertisemont, drawmg, permit application, zoning request,
computer design, etc.) or physical deimrcation (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?
A s defined in EPA’s storm water general permit for large
construction activity, an “operator” is the party or parties
that has
o Operational control of construction project plans
and specifications, including the ability to make
modifications to those plans and specifications, or
o Day-to-day operational control of those activities
that are necessary to ensure compliance with a
storm water 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 n re 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?
I n 1992, the Ninth Circuit court remanded for further
proceedings portions of EPA’s existing Phase I storm water
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 11 storm water 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 “storm water discharges
associated with small construction activity,” rather than
as another category under “storm water associated with
industrial activity”
Who Is Covered Under the Phase II
Construction Rule?
Sites Between One and Five Acres
The Storm Water Phase II Rule automatically designates, as
small construction activity under the NPDES storm water
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 comnon
plan of developmont or sale with a planned disturbance of
equal to or greater than I 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?
y es, but only for small, not large, construction activity
Under the Phase U Rule, NPDES permitting authorities
have the option of providing a waiver from the requireimnts
to operators of small construction activity who certify to
either one of two conditions.
0 Low predicted rainfall potential (i.e, activity occurs
during a negligible rainfall period), where the
rainfall erosivity factor (“R” in the Revised
Universal Sod Loss Equation [ RJJSLE]) is less than
5 during the period of construction activity; or
9 A determination that storm water 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 nee4ed 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 Sh 3.O-Constniction Program Overview
Pacie 3
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 constniction 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 0?
W aiver 0 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 onginally 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
tint-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 Charts detailing the value of the Rainfall Erosivity
Factor by particular regions can be found in Chapter 2 of
the RUSLE user’s guide, which can be downloaded at
httpi/www epa gov/owdsw/phase2
b. What is a “TMDL” in Waiver 0?
F or 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
n-nximum anx)unt 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
comnnn 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 storm water 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 0?
E PA 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 m 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 0, the operator of the construction site
would need to certify that its construction activity will take
place, and the storm water discharges will occur, within the
area covered either by the TMDLs or equivalent analysts A
certification form would likely be provided by the NPDES
permitting authonty for this purpose
What Does the Phase I I Construction Program
Require?
T he Phase II Final Rule requires operators of Phase IT
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, Tnbal, or local construction runoff
control programs (see Fact Sheets 2 6 and 2.7 for information
on the Phase II smell M54’s construction program) For
the Phase H 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 recommends that the NPDES permitting authon ties 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 H requirements would be similar to the
three general Phase I requirements summarized below.
U Submission of a Notice of intent (NO!) that
includes general information and a certification
that the activity will not impact endangered or
threatened species This certification is unique to
EPA’s NOl and is not a requirement of must
NPDES-delegated State’s NOIs,
3 The development and implementation of a Storm
Waler Pollution Prevention Plan (SWPPP) with
appropnate BMPs to imnirnize the discharge of
pollutants from the site; and
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
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Fact Sheet 3.0— Constnsction Proaram Overview
Page 4
o 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
Can the Permitting Authority Reference a
Qualifying Erosion and Sediment Control
Program in NPDES Construction Permits?
Y es. 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 requirenents
o Requirements for construction site operators to
implement appropriate erosion and sediment control
best management practices,
0 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,
0 Requirements for construction site operators to
develop and implement a storm water pollution
prevention plan, and
0 Requirements to submit a site plan for review that
incorporates consideration of potential water quality
impacts
lii 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 mare,
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?
T he approach and BMPs used for controlling pollutants in
storm water 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.
U Non-Structural BMPs
• Minimizing Disturbance
• Preserving Natural Vegetation
• Good Housekeeping
0 Structural BMPs
Erosion Con trots
• Mulch
• Grass
• Stockpile Covers
Sedinwnt Controls
• Silt Fence
• Inlet Protection
• Check Dame
• 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.
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Fact Sheet 3.0— Construction Program Overview Page 5
For Additional Information
Contact
U S EPA Office of Wastewater Management
• Internet www epa gov/npdes/stormwater
• Phone (202)-564-9545
I ’ 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. www nacdnet.org/resources/cdsonweb html
Reference Documents
Storm Water Phase H Final Rule Fact Sheet Series
• Internet. cipub epagov/npdes/stormwaierlswfinaLcfm
e Storm Water Phase H Fmal Rule (64 FR 68722)
• Internet www epagov/npdes/itgulations/phase2 pdf
Agricultural Handbook Number 703, Predicting Soil
Erosion by Water A Guide to Conservation Planning
With the Revised Universal Soil Lass Equation
(RUSLE), Chapter 2. pp 21-64, January 1997
• Internet 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
• Intcrnet www epa gov/OWOW/tniii
‘ NPDES General Permit for Storm Water Discharges
from Construction Activities (63 FR 7857)
• Internei www.epa gov/npdes/pubs/cgp-nat pdf
www epa govfnpdeslpubslcgp-nat2 pdf
www epa gov/npdeslpubs/cgp-nat3 pdf
www epa gov/npdes/pubs/cgp-nat4 pdf
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