Document ID: EPA-HQ-OW-2022-0834-0017
Agency: epa
Document Type: Rule
Title: National Pollutant Discharge Elimination System: Small Municipal Separate Storm Sewer Systems Urbanized Area; Clarification
Posted Date: 2023-06-12T04:00Z

[Federal Register Volume 88, Number 112 (Monday, June 12, 2023)]
[Rules and Regulations]
[Pages 37994-38000]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-12494]

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 122 and 123

[EPA-HQ-OW-2022-0834; FRL-10123-06-OW]
RIN 2040-AG27

NPDES Small MS4 Urbanized Area Clarification

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The U.S. Environmental Protection Agency (EPA) is finalizing 
clarifications to its National Pollutant Discharge Elimination System 
(NPDES) Stormwater Phase II regulations due to recent changes made by 
the Census Bureau. The changes to EPA's regulations are limited to 
clarifying that the designation criteria for small municipal separate 
storm sewer systems (MS4s), which have been used since the promulgation 
of the regulations in 1999, will remain the same. These clarifications 
are necessary due to the Census Bureau's recent decision to discontinue 
its practice of publishing the location of ``urbanized areas'' along 
with the 2020 Census and future censuses. The clarifications in this 
final rule replace the term ``urbanized area'' in the Phase II 
regulations with the phrase ``urban areas with a population of at least 
50,000,'' which is the Census

[[Page 37995]]

Bureau's longstanding definition of the term urbanized areas. This 
change allows NPDES permitting authorities to use 2020 Census and 
future Census data in a manner that is consistent with existing 
longstanding regulatory practice.

DATES: This final rule is effective on July 12, 2023.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OW-2022-0834. All documents in the docket are listed on the 
http://www.regulations.gov website. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available electronically through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Heather Huddle, Water Permits Division 
(MC4203), Environmental Protection Agency, 1200 Pennsylvania Ave. NW, 
Washington, DC 20004; telephone number: (202) 564-7932; email address: 
[email protected].

SUPPLEMENTARY INFORMATION: This action is limited to clarifying that 
EPA is retaining the existing threshold for automatic designation of 
small MS4s for regulation under the Phase II stormwater permitting 
regulations. The threshold for automatic designation was used following 
the 2000 and 2010 Censuses and is based on the MS4 being in an 
urbanized area of 50,000 or more people. This final rule maintains the 
threshold for automatic designations of small MS4s and ensures that the 
designation of new MS4s will continue as originally required under the 
Phase II regulations.
    EPA's action finalizes changes that were proposed on December 2, 
2022 (87 FR 74066) in tandem with the publication of a direct final 
rule (87 FR 73965, December 2, 2022), both of which included the same 
regulatory changes. EPA withdrew the direct final rule (88 FR 10851, 
February 22, 2023) after receiving an adverse comment.

Table of Contents

I. General Information
    A. Does this action apply to me?
    B. What action is EPA taking?
    C. What is the agency's authority for taking this action?
    D. Background
II. Rationale and Summary of the Rule
    A. Why a Change to the Phase II Regulations Is Appropriate
    B. Rationale for Clarification to Phase II Regulations
    C. Summary of Changes to Phase II Regulations
    D. Costs of This Action
    E. Implementation and Technical Assistance
III. Statutory and Executive Orders Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    K. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

    Entities regulated by this action include:

------------------------------------------------------------------------
                                                         North American
                                                            industry
           Category              Examples of regulated   classification
                                       entities          system (NAICS)
                                                              code
------------------------------------------------------------------------
Federal and state government..  EPA or state NPDES                924110
                                 stormwater permitting
                                 authorities.
Local governments.............  Operators of small                924110
                                 municipal separate
                                 storm sewer systems.
State government..............  State departments of              926120
                                 transportation.
Military......................  Federal military bases            928110
Public academic institutions..  Publicly-administered             611310
                                 colleges,
                                 universities, and
                                 professional schools.
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table includes the types of entities that EPA is now aware 
could potentially be regulated by this action. Other types of entities 
not included could also be regulated. To determine whether your entity 
is regulated by this action, you should carefully examine the 
applicability criteria found in 40 CFR 122.28, 122.32, and 122.35, and 
the discussion in the preamble. If you have questions regarding the 
applicability of this action to a particular entity, consult the person 
listed in the FOR FURTHER INFORMATION CONTACT section.

B. What action is EPA taking?

    EPA is clarifying its NPDES Phase II regulations due to recent 
changes made by the Census Bureau. The changes to EPA's regulations are 
limited to clarifying that the designation criteria for small MS4s, 
which have been used since the promulgation of the regulations in 1999, 
will remain the same. The clarification replaces the term previously 
used by the Census Bureau, ``urbanized area,'' with the phrase ``urban 
areas with a population of at least 50,000,'' which is the Census 
Bureau's longstanding criteria for defining urbanized areas.

C. What is the Agency's authority for taking this action?

    The authority for this rulemaking is the Federal Water Pollution 
Control Act, 33 U.S.C. 1251 et seq., including sections 402 and 501.

D. Background

1. Statutory and Regulatory Overview
    Stormwater discharges are subject to regulation under section 
402(p) of the Clean Water Act (CWA). Under this provision, Congress 
required the following stormwater discharges initially to be subject to 
NPDES permitting requirements: stormwater discharges for which NPDES 
permits were issued prior to February 4, 1987; discharges ``associated 
with industrial activity;'' discharges from MS4s serving

[[Page 37996]]

populations of 100,000 or more; and any stormwater discharge determined 
by EPA or a state to ``contribute[ ] to a violation of a water quality 
standard or [to be] a significant contributor of pollutants to waters 
of the United States.'' Congress further directed EPA to study other 
stormwater discharges and determine which discharges needed additional 
controls.
    EPA developed the stormwater regulations under section 402(p) of 
the CWA in two phases, as directed by the statute. In the first phase, 
under section 402(p)(4) of the CWA, EPA promulgated regulations 
establishing application and other NPDES permit requirements for 
stormwater discharges from medium (serving populations of 100,000 and 
up to 250,000) and large (serving populations of 250,000 or more) MS4s, 
and stormwater discharges associated with industrial activity. EPA 
published the final Phase I rule on November 16, 1990. 55 FR 47990. The 
Phase I rule, among other things, defined ``municipal separate storm 
sewer'' as publicly-owned conveyances or systems of conveyances that 
discharge to waters of the United States and are designed or used for 
collecting or conveying stormwater, are not combined sewers, and are 
not part of a publicly-owned treatment works. 40 CFR 122.26(b)(8).
    In the second phase, sections 402(p)(5) and (6) of the CWA required 
EPA to conduct a study to identify other stormwater discharges that 
needed further controls ``to protect water quality,'' report to 
Congress on the results of the study, and designate for regulation 
additional categories of stormwater discharges not regulated in Phase I 
in consultation with state and local officials. EPA promulgated the 
Phase II rule on December 8, 1999, designating discharges from certain 
small MS4s and from small construction sites (disturbing equal to or 
greater than one acre and less than five acres) and requiring NPDES 
permits for these discharges. 64 FR 68722 (December 8, 1999). A 
regulated small MS4 is generally defined as any MS4 that is not already 
covered by the Phase I program and is located within the ``urbanized 
area'' boundary as determined by the latest U.S. Decennial Census. 40 
CFR 122.32(a)(1) (``you are regulated if you operate a small MS4, 
including but not limited to systems operated by Federal, State, 
Tribal, and local governments, including State departments of 
transportation; and . . . [y]our small MS4 is located in an urbanized 
area as determined by the latest Decennial Census by the Bureau of the 
Census.'').
    Separate storm sewer systems such as those serving military bases, 
universities, large hospitals or prison complexes, and highways are 
also included in the definition of ``small MS4.'' 40 CFR 122.26(b)(16). 
In addition, the Phase II rule includes authority for EPA (or states 
authorized to administer the NPDES program) to require NPDES permits 
for currently unregulated stormwater discharges through a designation 
process. 40 CFR 122.26(a)(9)(i)(C) and (D). Other small MS4s located 
outside of an urbanized area may be designated as a regulated small MS4 
if the NPDES permitting authority determines that its discharges cause, 
or have the potential to cause, an adverse impact on water quality. 40 
CFR 122.32(a)(2), 123.35(b)(3).
2. History of Using Urbanized Area Population Threshold for Small MS4 
Designations
    Beginning with the 1950 Census, the Census Bureau defined 
``urbanized area'' as ``one or more cities of 50,000 or more and all 
the nearby closely settled suburban territory, or urban fringes.'' \1\ 
This definition was in effect when EPA promulgated the Phase II Rule in 
1999, and for the two censuses (2000 and 2010 Census) that have been 
published since then.\2\ The Census Bureau's use of this population 
threshold is significant for the Phase II permit program because where 
an MS4 is located within an area identified in the latest decennial 
Census as having a minimum population of 50,000 or more people (i.e., 
in an ``urbanized area''), the MS4 is automatically designated as 
regulated under the Phase II regulations.
---------------------------------------------------------------------------

    \1\ 1950 Census of Population--Preliminary Counts, Population of 
Urbanized Areas: April 1, 1950, U.S. Department of Commerce, Bureau 
of the Census. Series PC-3 No. 9. February 1, 1951. See https://www2.census.gov/library/publications/decennial/1950/pc-03/pc-3-09.pdf.
    \2\ Urbanized areas have been defined by the Census Bureau as 
``urban areas that contain 50,000 or more people. . .''. See 76 FR 
53030, 53039 (August 24, 2011); and 67 FR 11663, 116667 (March 15, 
2002).
---------------------------------------------------------------------------

    The Phase II regulations have referred to the term ``urbanized 
area'' since the small MS4 program's inception and this term has always 
been used synonymously with the 50,000 population threshold. When EPA 
initially promulgated the Phase II regulations, EPA explained that it 
was adopting the Census Bureau's definition of ``urbanized area'' as 
one of the designation criteria for small MS4s and provided a 
definition of ``urbanized area'' that was identical to the Census 
Bureau's definition. EPA stated in the preamble to the Phase II rule 
that ``[u]nder the Bureau of the Census definition of `urbanized area,' 
adopted by EPA for the purposes of this final rule, `an urbanized area 
(UA) comprises a place and the adjacent densely settled surrounding 
territory that together have a minimum population of 50,000 people.' '' 
64 FR 68722, 68751 (December 8, 1999).
    EPA acknowledged that the Census Bureau could in the future change 
the criteria by which it defines ``urbanized area,'' which would then 
in turn affect the way in which new small MS4s would be automatically 
designated. It is for this reason that EPA explained in the Phase II 
rule preamble that new MS4 designations ``will be governed by the 
Bureau of the Census' definition of an urbanized area in effect for 
that year.'' 64 FR 68722, 68751 (December 8, 1999). However, the Census 
Bureau has not changed the 50,000 population threshold since they 
adopted it 70 years ago. From the small MS4 permit program's inception 
in 1999, therefore, EPA and state permitting authorities have always 
relied on the 50,000 population threshold to automatically designate 
and regulate MS4s. It is only now with the 2020 Census that the Census 
Bureau has announced its decision to no longer separately identify 
``urbanized areas.'' 87 FR 16706, 16707 (March 24, 2022).

II. Rationale and Summary of the Rule

A. Why a Change to the Phase II Regulations Is Appropriate

    The original Phase II regulatory text did not explicitly instruct 
EPA how to treat the designation of MS4s in the event that the Census 
Bureau's decennial censuses determines that it will no longer 
separately identify ``urbanized areas.'' For the 1999 Phase II rule, 
EPA always intended the universe of regulated small MS4s to grow in a 
manner commensurate with the growth of ``urbanized areas'' as 
identified by the latest decennial census. However, while the Phase II 
rule preamble explained that additional MS4s would be designated in 
accordance with the latest census definition of ``urbanized area,'' it 
did not provide instruction on what to do if a decennial census no 
longer identifies the location of such urbanized areas.\3\

[[Page 37997]]

EPA is taking this action to address the Census Bureau's changes and 
clarify for permitting authorities and the public that the scope of 
which small MS4s are regulated will not change, and that EPA will rely 
on what that term has always meant rather than having the regulations 
reference an out-of-date term.
---------------------------------------------------------------------------

    \3\ EPA stated in the Phase II rule preamble that: ``Additional 
designations based on subsequent census years will be governed by 
the Bureau of the Census' definition of an urbanized area in effect 
for that year. Based on historical trends, EPA expects that any area 
determined by the Bureau of the Census to be included within an 
urbanized area as of the 1990 Census will not later be excluded from 
the urbanized area as of the 2000 Census. However, it is important 
to note that even if this situation were to occur, for example, due 
to a possible change in the Bureau of the Census' urbanized area 
definition, a small MS4 that is automatically designated into the 
NPDES program for storm water under an urbanized area calculation 
for any given Census year will remain regulated regardless of the 
results of subsequent urbanized area calculations.'' 64 FR 68751 
(December 8, 1999).
---------------------------------------------------------------------------

B. Rationale for Clarification to Phase II Regulations

    The most straightforward way for EPA to clarify its regulations in 
a manner that maintains program continuity and consistency is to 
replace the reference to ``urbanized area'' in the Phase II regulations 
with text that replicates the 50,000 population threshold on which the 
Census Bureau and NPDES authorities have historically relied. As 
discussed in section II.D.2 of this preamble, from the inception of the 
small MS4 permitting program, the 50,000 population threshold has been 
used synonymously with the term ``urbanized area'' by both the Census 
Bureau and NPDES permitting authorities. Replacing the term ``urbanized 
area'' with text that incorporates this same 50,000 population 
threshold means that the existing method for designating small MS4s 
following the latest decennial census will be identical to how it has 
always been implemented. This change ensures that there is no 
disruption in the designation of additional MS4s and that the program 
will be implemented in a historically consistent manner.
    Substituting the obsolete references to ``urbanized areas'' with 
the 50,000 population threshold also ensures that new Census 2020 
mapping data and subsequent census mapping data can be used seamlessly 
to identify newly regulated MS4s. Prior to the recent Census Bureau 
changes, the location of any ``urbanized areas'' would have been 
automatically identified with any decennial census. Moving forward, 
however, each decennial census will be limited to identifying ``urban 
areas'' without identifying ``urbanized areas'' within those areas. 
Even though ``urbanized area'' locations will no longer be provided as 
part of the 2020 Census and future censuses, the Census Bureau will 
continue to provide population data for each identified urban area.\4\ 
The Census Bureau published these data to its website in January 2023 
at https://www.census.gov/programs-surveys/geography/guidance/geo-areas/urban-rural.html. These population data will enable EPA and state 
permitting authorities to identify which urban areas have populations 
of 50,000 or more people and, therefore, to provide the necessary 
information to designate new MS4s.
---------------------------------------------------------------------------

    \4\ In its 2020 Urban Areas Frequent Asked Questions, the Census 
Bureau provided the following answer in response to the question 
``Is it true that the Census Bureau is no longer defining urbanized 
areas?'': ``No. The Census Bureau will no longer identify an 
individual urban area as either an urbanized area or an urban 
cluster. We will refer to all areas as ``urban areas'' regardless of 
population size. We will publish population and housing counts for 
each urban area when we announce results of the 2020 Census urban 
area delineation. Data users and program will be able to use those 
counts and subsequent American Community Survey estimates to 
categorize urban areas according to population size.'' (emphasis 
added) See https://www2.census.gov/geo/pdfs/reference/ua/2020_Urban_Areas_FAQs.pdf.
---------------------------------------------------------------------------

C. Summary of Changes to Phase II Regulations

    The changes to the Phase II regulations are limited to replacing 
the existing references to ``urbanized area'' as a criterion for 
designating small MS4s for regulation with text that incorporates the 
underlying population threshold associated with that term, or more 
specifically ``urban areas with a population of 50,000 or more 
people.'' This change is made in the following specific sections:
     40 CFR 122.28(a)(1)(vi): This provision describes the 
requirement that general permits can only be used to provide coverage 
to discharges in a specific geographic area. The final rule replaces 
the original reference to ``urbanized areas'' in one of the examples of 
geographic or political boundary areas that meet this requirement with 
the described 50,000 population threshold.
     40 CFR 122.32(a)(1): This original provision specified 
that small MS4s located in ``urbanized areas'' are regulated as small 
MS4s. The reference to ``urbanized areas'' is replaced by the described 
50,000 population threshold.
     40 CFR 122.32(d): The original provision indicated that 
small MS4s regulated under 40 CFR 122.32(a)(1) for ``urbanized areas'' 
may be eligible for an NPDES waiver if they meet the applicable 
criteria. The reference to ``urbanized areas'' is substituted with a 
reference to the revised text in 40 CFR 122.32(a)(1).
     40 CFR 122.33(b)(3): The original provision referenced the 
ability of regulated small MS4s located in the same ``urbanized area'' 
as a medium or large MS4 to be included as a limited co-permittee in 
the same NPDES permit as the medium or large MS4. The reference to 
``urbanized area'' is modified to read ``urban area'' instead.
     40 CFR 123.35(b)(1)(ii): The original provision included a 
reference to an ``urbanized area'' in the context of regulatory 
guidance on criteria that state permitting authorities may use to 
designate other small MS4s for regulation, including ``contiguity to an 
urbanized area.'' The reference to ``urbanized area'' is replaced by 
the described 50,000 population threshold.
     40 CFR 123.35(b)(2): The original provision included a 
reference to an ``urbanized area'' in the context of applying state 
permitting authority criteria for designating additional small MS4s for 
regulation, including MS4s located outside of an ``urbanized area'' 
serving a jurisdiction with a population density of at least 1,000 
people per square mile and a population of at least 10,000. The 
reference to ``urbanized area'' is replaced by the described 50,000 
population threshold.
     40 CFR 123.35(d)(1): The original provision indicated that 
small MS4s regulated under 40 CFR 122.32(a)(1) for ``urbanized areas'' 
may be eligible for an NPDES waiver if they meet the applicable 
criteria. The reference to ``urbanized areas'' is substituted with the 
described 50,000 population threshold.

D. Costs of This Action

    The regulatory clarifications in this rule ensure that the 
population basis for regulating small MS4s remains the same. As a 
result, these clarifications do not result in increased costs to small 
MS4 permittees or to state and EPA permitting programs, nor do the rule 
changes result in regulating additional MS4s beyond what was required 
by the 1999 Phase II regulations.

E. Implementation and Technical Assistance

    EPA will be providing technical assistance to permitting 
authorities in several ways to help with the implementation of the MS4 
program following publication of the new census data. The following is 
a summary of EPA's ongoing technical assistance activities:
     Publish new MS4 mapping information: EPA will work with 
permitting authorities on new MS4 mapping information. Using the now 
published 2020 Census urban area information, EPA will identify which 
urban areas have a population of 50,000 or more people. EPA will also 
use the 2020 Census data to identify where urban areas with a 
population of 50,000 or more people are located in the United States 
and where these areas are located

[[Page 37998]]

with respect to municipal boundaries. EPA will share this information 
with permitting authorities to enable them to determine which 
jurisdictions are likely operating MS4s within urban areas that meet 
the 50,000 population threshold. EPA will provide mapping information 
that compares the 2010 Census and 2020 Census locations of these urban 
areas. Permitting authorities will be able to use this information to 
pinpoint the location of newly designated MS4s and compare how the 
urban area boundaries have changed for existing MS4s since the 2010 
Census.
     Provide permitting authorities with a preliminary list of 
newly designated MS4s: To assist NPDES permitting authorities, EPA is 
using the mapping information described under the previous bullet point 
to preliminarily identify newly designated MS4s that are located within 
urban areas with a population of 50,000 or more people. EPA provided a 
similar list of newly designated MS4s following the 2010 Census. 
Permitting authorities are then free to evaluate the MS4s identified on 
this list to determine if the information is accurate and whether any 
changes are needed. Permitting authorities may also need to assess any 
requests for permitting waivers submitted by newly designated MS4s that 
have been notified of their designation by the permitting authority.
     Provide guidance materials for permitting authorities: EPA 
is providing additional guidance related to the process of permitting 
newly designated MS4s that NPDES authorities may choose to use. EPA 
provided similar guidance following the publication of the 2010 Census, 
which included tips on the suggested steps to follow from initial 
contact with the new MS4 operators to including them in the applicable 
NPDES permit. After the 2010 Census, EPA also provided a letter 
template that permitting authorities could use to inform new MS4 
operators of their designation and what to expect from the permitting 
process moving forward. The Agency is updating these materials for the 
2020 Census and will explore what additional technical assistance may 
be needed.
     Rescind interim guidance: In 2022, EPA published on its 
website Interim Guidance on Census Elimination of ``Urbanized Areas'' 
(see https://www.epa.gov/npdes/interim-guidance-census-elimination-urbanized-area-definition). The guidance was intended to provide 
interim recommendations to permitting authorities regarding the 
implementation of their small MS4 permitting programs following the 
finalization of the Census Bureau's designation criteria changes while 
EPA evaluated how best to clarify its regulations. With the publication 
of this final rule, the interim guidance is no longer necessary and has 
been rescinded.

III. Statutory and Executive Orders Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 14094: Modernizing Regulatory Review

    This action is not a significant regulatory action as defined in 
Executive Order 12866, as amended by Executive Order 14094, and was 
therefore not subject to a requirement for Executive Order 12866 
review.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA. OMB has previously approved the information collection 
activities contained in the existing regulations and has assigned OMB 
control number 2040-0004. This rule contains no new requirements for 
reporting and recordkeeping.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, EPA concludes that the impact of concern for 
this rule is any significant adverse economic impact on small entities 
and that the Agency is certifying that this rule will not have a 
significant economic impact on a substantial number of small entities 
because the rule has no net burden on the small entities subject to the 
rule. EPA limits this rule to substituting the use of the term 
``urbanized area'' with the underlying population criteria that has 
been used synonymously with this term since the 1999 promulgation of 
the regulations in four subsections of the Phase II regulations. See 
discussion in sections II.B and C of this preamble. Although making 
this clarification is important to ensure program continuity and 
consistency, EPA views this change as akin to a clerical correction to 
remove an obsolete term and ensure that program applicability remains 
unchanged. EPA has therefore concluded that this action will have no 
net regulatory burden for all directly regulated small entities.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The action imposes no enforceable duty on any state, 
local or tribal governments, or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. It will not have substantial direct effects on 
tribal governments, on the relationship between the Federal government 
and Indian tribes, or on the distribution of power and responsibilities 
between the Federal government and Indian tribes, as specified in 
Executive Order 13175. Thus, Executive Order 13175 does not apply to 
this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that EPA has reason to believe may disproportionately affect children, 
per the definition of ``covered regulatory action'' in section 2-202 of 
the Executive Order. This action is not subject to Executive Order 
13045 because it does not concern an environmental health risk or 
safety risk.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    This rule does not involve technical standards.

[[Page 37999]]

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
Federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on minority populations (people of color and/or indigenous 
peoples) and low-income populations.
    EPA believes that the human health and environmental conditions 
that exist prior to this action do not result in disproportionate and 
adverse effects on people of color, low-income populations, and/or 
indigenous peoples. This action makes a technical clarification to a 
previously promulgated regulatory action and will not change the human 
health and environmental conditions that currently exist with the 
implementation of the Phase II regulations.
    EPA believes that this action is not likely to result in new 
disproportionate and adverse effects on people of color, low-income 
populations and/or indigenous peoples. This regulatory action is a 
technical clarification to a previously promulgated regulatory action 
and does not have any disproportionate and adverse impact on people of 
color, low-income populations, and/or indigenous peoples.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects

40 CFR Part 122

    Environmental protection, Stormwater, Water pollution.

40 CFR Part 123

    Environmental protection, Stormwater, Water pollution.

Michael S. Regan,
Administrator.

    For the reasons stated in the preamble, EPA amends 40 CFR parts 122 
and 123 as set forth below:

PART 122--EPA ADMINISTERED PERMIT PROGRAMS: THE NATIONAL POLLUTANT 
DISCHARGE ELIMINATION SYSTEM

0
1. The authority citation for part 122 continues to read as follows:

    Authority: The Clean Water Act, 33 U.S.C. 1251 et seq.

0
2. Amend Sec.  122.28 by revising paragraph (a)(1)(vi) to read as 
follows:

Sec.  122.28  General permits (applicable to State NPDES programs, see 
Sec.  123.25).

    (a) * * *
    (1) * * *
    (vi) Urban areas with a population of 50,000 or more people as 
determined by the latest Decennial Census by the Bureau of the Census; 
or
* * * * *

0
3. Amend Sec.  122.32 by revising paragraphs (a)(1) and (d) 
introductory text to read as follows:

Sec.  122.32  As an operator of a small MS4, am I regulated under the 
NPDES storm water program?

    (a) * * *
    (1) Your small MS4 is located in an urban area with a population of 
50,000 or more people as determined by the latest Decennial Census by 
the Bureau of the Census. (If your small MS4 is not located entirely 
within an urban area with a population of 50,000 or more people, only 
the portion that is within this urban area is regulated); or
* * * * *
    (d) The NPDES permitting authority may waive permit coverage if 
your MS4 serves a population of less than 1,000 within the urban area 
identified in paragraph (a)(1) of this section and you meet the 
following criteria:
* * * * *

0
4. Amend Sec.  122.33 by revising paragraph (b)(3) to read as follows:

Sec.  122.33  Requirements for obtaining permit coverage for regulated 
small MS4s.

* * * * *
    (b) * * *
    (3) Co-permittee alternative. If the regulated small MS4 is in the 
same urban area as a medium or large MS4 with an NPDES storm water 
permit and that other MS4 is willing to have the small MS4 operator 
participate in its storm water program, the parties may jointly seek a 
modification of the other MS4 permit to include the small MS4 operator 
as a limited co-permittee. As a limited co-permittee, the small MS4 
operator will be responsible for compliance with the permit's 
conditions applicable to its jurisdiction. If the small MS4 operator 
chooses this option it must comply with the permit application 
requirements of Sec.  122.26, rather than the requirements of paragraph 
(b)(2)(i) of this section. The small MS4 operator does not need to 
comply with the specific application requirements of Sec.  
122.26(d)(1)(iii) and (iv) and (d)(2)(iii) (discharge 
characterization). The small MS4 operator may satisfy the requirements 
in Sec.  122.26(d)(1)(v) and (d)(2)(iv) (identification of a management 
program) by referring to the other MS4's storm water management 
program.
* * * * *

PART 123--STATE PROGRAM REQUIREMENTS

0
5. The authority citation for part 123 continues to read as follows:

    Authority: Clean Water Act, 33 U.S.C. 1251 et seq.

0
6. Amend Sec.  123.35 by revising paragraphs (b)(1)(ii), (b)(2), and 
(d)(1) introductory text to read as follows:

Sec.  123.35  As the NPDES Permitting Authority for regulated small 
MS4s, what is my role?

* * * * *
    (b) * * *
    (1) * * *
    (ii) Guidance: For determining other significant water quality 
impacts, EPA recommends a balanced consideration of the following 
designation criteria on a watershed or other local basis: discharge to 
sensitive waters, high growth or growth potential, high population 
density, contiguity to an urban area with a population of 50,000 people 
or more as determined by the latest Decennial Census by the Bureau of 
the Census, significant contributor of pollutants to waters of the 
United States, and ineffective protection of water quality by other 
programs;
    (2) Apply such criteria, at a minimum, to any small MS4 located 
outside of an urban area with a population of 50,000 people or more as 
determined by the latest Decennial Census by the Bureau of the Census 
serving a jurisdiction with a population density of at least 1,000 
people per square mile and a population of at least 10,000;
* * * * *

[[Page 38000]]

    (d) * * *
    (1) You may waive permit coverage for each small MS4s in 
jurisdictions with a population under 1,000 within the urban area with 
a population of 50,000 people or more as determined by the latest 
Decennial Census by the Bureau of the Census where all the following 
criteria have been met:
* * * * *
[FR Doc. 2023-12494 Filed 6-9-23; 8:45 am]
BILLING CODE 6560-50-P