UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
f	REGION VIII
999 18th STREET - SUITE 500
DENVER, COLORADO 80202-2466
EPA REGION VIII
] CLARIFICATION OF THE DEFINITION OF
STORM WATER DISCHARGES
ASSOCIATED WITH INDUSTRIAL ACTIVITY
Updated May 1993
Printed on Recycled Paper

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The following is intended to provide some clarification of the definition given in the Code of Federal
Regulations (CFR) at 40 CFR 1 22.26(b)(14) (November 1 6, 1 990 Federal Register, page 48065). A facility is
required to apply for, and obtain a permit, if the facility meets the definition of "storm water discharge
associated with industrial activity" and they have a point source discharge (see page 7) of storm water to
waters of the United States or that discharge through municipal separate storm sewer systems.
The paragraphs or sentences in italics following each of the 11 Roman numerals (e.g., (i)) is the same wording
as in the regulation. All of the other material to the next Roman numeral is intended to provide additional
information.
The term "storm water discharge associated with industrial activity" means the discharge from any
conveyance which is used for collecting and conveying storm water and which is directly related to
manufacturing, processing, or raw materials storage areas at an industrial plant. The term does not include
discharges from facilities or activities excluded from the NPDES program under 40 CFR part 122. For the
industries identified bv categories (i) through (x). starting on oaae 3. the term includes, but is not limited to:
(These are applicable areas)
•	storm water discharges from industrial plant yards;
•	immediate access roads and rail lines used or traveled by carriers of raw materials,
manufactured products, waste material, or by-products used or created by the facility;
•	material handling sites;
•	refuse sites;
•	sites used for the application or disposal of process waste waters (as defined at 40 CFR part
401);
•	sites used for the storage and maintenance of material handling equipment;
•	sites used for residual treatment, storage, or disposal;
•	shipping and receiving areas;
•	manufacturing buildings;
•	storage areas (including tank farms) for raw materials, and intermediate and finished products;
and
•	areas where industrial activity has taken place in the past and significant materials remain and
are exposed to storm water.
For industries identified by category (xi), the term includes only storm water discharges from all the areas
(except access roads and rail lines) that are listed above, where material handling equipment or activities, raw
materials, intermediate products, final products, waste materials, by-products, or industrial machinery are
exposed to storm water1. For the purposes of this definition, material handling activities include the storage,
loading and unloading, transportation, or conveyance of any raw material, intermediate product, finished
product, by-product or waste product. The term excludes areas located on plant lands separate from the
plant's industrial activities, such as office buildings and accompanying parking lots as long as the drainage
from the excluded areas is not mixed with storm water drained from the areas described above.
The following is from the November 16, 1990 Federal Register (page 48008):
"The critical distinction between the facilities identified at 40 CFR 122.26(b)(14)(xi) and the facilities
identified at 40 CFR 122.26(b)(14)(i)-(x) is that the former are not classified as having "storm water
discharges associated with industrial activity" unless certain materials or activities are exposed to
storm water. Storm water discharges from the latter set of facilities are considered to be "associated
with industrial activity" regardless of the actual exposure of these same materials or activities to storm
water."
1 (Comment: If everything except the access roads and rail lines are under a roof, the facilities
in category (xi) which are not otherwise included within categories (ii)-(x) do not have to apply for a
permit unless designated.)
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THE ELEVEN CATEGORIES DEFINED BY THE REGULATION
(40 CFR 122.26(b)(14):
(i) Facilities subject to storm water effluent limitations guidelines, new source performance standards, or
toxic pollutant effluent standards under 40 CFR subchapter N Iexcept facilities with toxic pollutant
effluent standards which are exempted under category (xil);
Effluent limitations guidelines that include storm water:
40
CFR
411
Cement Manufacturing
40
CFR
412
Feedlots
40
CFR
418
Fertilizer Manufacturing
40
CFR
419
Petroleum Refining
40
CFR
422
Phosphate Manufacturing
40
CFR
423
Steam Electric Power Generating
40
CFR
434
Coal Mining
40
CFR
436
Mineral Mining and Processing
40
CFR
440
Ore Mining and Dressing
40
CFR
443
Asphalt Emulsion portion of Paving and Roofing Materials
The phrase "toxic pollutant effluent standards" has been used by EPA exclusively as a technical
reference to the standards at 40 CFR Part 129. Part 129 applies only to owners or operators of
specified types of facilities (e.g., manufacturing, formulating, etc.) that involve the use of any of the
following toxic pollutants: Aldrin/Dieldrin; DDT, DDD, DDE; Endrin; Toxaphene; Benzidine; and
Polychlorinated biphenlys (PCBs).
Most effluent limitations guidelines listed in 40 CFR Subchapter N contain New Source Performance
Standards (NSPS). The following categories of Subchapter N facilities do nal have new source
performance standards. All other categories have at least one subcategory with new source
performance standards.
Oil and Gas Extraction (40 CFR 435)
Mineral Mining and Processing (40 CFR 436)
Gum and Wood Chemicals Manufacturing (40 CFR 454)
Pesticide Chemicals (40 CFR 455)
Explosives Manufacturing (40 CFR 457)
Photographic (40 CFR 459)
Hospital (40 CFR 460)
(ii) Facilities classified as Standard Industrial Classifications 24 (except 2434), 26 (except 265 and 267),
28 (except 283 and 285), 29, 311,32 (except 323), 33, 3441, 373;
24 Lumber and wood products, except furniture
Does not include 2434
2434 - wood kitchen cabinets
Note: SIC code 24 includes 241, logging, and 242, sawmills. At 40 CFR 122.27(b),
"Silvicultural point source" is defined as any discernible, confined and discrete
conveyance related to rock crushing, gravel washing, log sorting, or log storage
facilities which are operated in connection with silvicultural activities and from which
pollutants are discharged into waters of the United States. All other discharges from
silvicultural activities are non-point sources and not subject to the requirements of this
program.
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26 Paper and allied products
Does not include 265 and 267
265 - paperboard containers and boxes
267 - misc. converted paper products
28	Chemicals and allied products
Does not include 283 and 285
283 - Drugs
285 - Paints and allied products
29	Petroleum refining and related industries
311 Leather tanning and finishing
32	Stone, clay, glass, and concrete products
Does not include 323
323 - Products of purchased glass
33	Primary metal industries
3441 Fabricated structural metal
373 Ship and boat building and repairing
(iii) Facilities classified as Standard Industrial Classifications 10 through 14 (mineral industry) including
active or inactive mining operations (except for areas of coal mining operations no longer meeting the
definition of a reclamation area under 40 CFR 434.11(1) because the performance bond issued to the
facility by the appropriate SMCRA authority has been released, or except for areas of non-coal mining
operations which have been released from applicable State or Federal reclamation requirements after
December 17, 1990) and oil and gas exploration, production, processing, or treatment operations, or
transmission facilities that discharge storm water contaminated by contact with or that has come into
contact with, any overburden, raw material, intermediate products, finished products, byproducts or
waste products located on the site of such operations; (inactive mining operations are mining sites
that are not being actively mined, but which have an identifiable owner/operator; inactive mining sites
do not include sites where mining claims are being maintained prior to disturbances associated with
the extraction, beneficiation, or processing of mined materials, nor sites where minimal activities are
undertaken for the sole purpose of maintaining a mining claim);
10	Metal mining
12	Coalmining
13	Oil and gas extraction
14	Mining and quarrying of nonmetallic minerals, except fuels
The operator of an existing or new discharge composed entirely of storm water from an oil or gas
exploration, production, processing, or treatment operation, or transmission facility is not required to
submit a permit application in accordance with paragraph (c)(1)(i) of this section, unless the facility:
(A)	Has had a discharge of storm water resulting in the discharge of a reportable quantity for
which notification is or was required pursuant to 40 CFR 117.21 or 40 CFR 302.6 at anytime
since November 16, 1987; or
(B)	Has had a discharge of storm water resulting in the discharge of a reportable quantity for
which notification is or was required pursuant to 40 CFR 110.6 at any time since November
16, 1987; or
(C)	Contributes to a violation of a water quality standard.
(Comment: On a practical basis the most stringent requirement of (A) and (B) above is not to have a
visible sheen of oil reach waters of the United States (or waters of the State if a delegated program).
Depending on the pollutant, the minimum reportable quantities for hazardous substances range from
one (1) pound to 5,000 pounds per day.)
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The operator of an existing or new discharge composed entirely of storm water from a mining
operation is not required to submit a permit application unless the discharge has come into contact
with, any overburden, raw material, intermediate products, finished product, byproduct or waste
products located on the site of such operations.
(iv) Hazardous waste treatment, storage, or disposal facilities, including those that are operating under
interim status or a permit under subtitle C of RCRA;
(v) Landfills, land application sites, and open dumps that receive or have received any industrial wastes
(waste that is received from any of the facilities described in any of these categories (i) - (xi)j including
those that are subject to regulation under subtitle D of RCRA;
(vi) Facilities involved in the recycling of materials, including metal scrapyards, battery reclaimers, salvage
yards, and automobile junkyards, including but limited to those classified as Standard Industrial
Classification 5015 and 5093;
5015 Motor vehicle parts, used
5093 Scrap and waste materials
- includes facilities that recycle scrap metal, plastic, paper, glass, aluminum etc.
Gas stations or repair shops that collect tires or batteries are not included in this category.
Municipal waste collection sites that collect bottles, cans or newspapers for recycling purposes are
also not covered.
(vii) Steam electric power generating facilities, including coal handling sites;
Heat capture co-generation facilities are not covered; however, duel fuel co-generation facilities, and
steam electric generators at educational facilities are covered, and are required to apply for a permit.
(viii) Transportation facilities classified as Standard Industrial Classifications 40, 41, 42 (except 4221-25),
43, 44, 45, and 5171 which have vehicle maintenance shops, equipment cleaning operations, or
airport deicing operations. Only those portions of the facility that are either involved in vehicle
maintenance (including vehicle rehabilitation, mechanical repairs, painting, fueling, and lubrication),
equipment cleaning operations, airport deicing operations, or which are otherwise identified under
paragraphs (bid4) (i)-(vii) or (ix)-(xi) of this section are associated with industrial activity;
40	Railroad transportation
41	Local and suburban transit and interurban highway passenger transportation
42	Motor freight transportation and warehousing
Does not include 4221-25
4221	- Farm product warehousing & storage
4222	- Refrigerated warehousing & storage
4225 - General warehousing and storage
43	United States Postal Service
44	Water Transportation
45	Transportation by air
5171 Petroleum bulk stations & terminals
Does not include gas stations, automotive repair shops or truck stops.
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(ix) Treatment works treating domestic sewage or any other sewage sludge or wastewater treatment
device or system, used in the storage treatment, recycling, and reclamation of municipal or domestic
sewage, including land dedicated to the disposal of sewage sludge that are located within the confines
of the facility, with a design flow of 1.0 mgd or more, or required to have an approvedpretreatment
program under 40 CFR part 403. Not included are farm lands, domestic gardens or lands used for
sludge management where sludge is beneficially reused and which are not physically located in the
confines of the facility, or areas that are in compliance with section 405 of the CWA;
(x) Construction activity including clearing, grading and excavation activities except: operations that result
in the disturbance of less than five acres of total land area which are not part of a larger common plan
of development or sale;1
Any construction activity that results in the disturbance of five acres of land or more in total is
covered by the rule. Such activities may include road building (including those associated with oil and
gas production), construction of houses, office buildings, industrial buildings, pipelines, and demolition
activity. This does not apply to agricultural or silvicultural activities, which are exempt from NPDES
permit requirements under 40 CFR 122.3.
"Part of a larger common plan of development or sale" describes a situation in which multiple
construction activities are occurring on a contiguous area. The activities could be taking place at
different times on different schedules. The key is that these different construction activities are part
of one common plan, common blueprint, or development.
(xi) Facilities under Standard Industrial Classifications 20, 21, 22, 23, 2434, 25, 265, 267, 27, 283, 285,
30, 31 (except 311), 323, 34 (except 3441), 35, 36, 37 (except 373), 38, 39, 4221-25, (and which
are not otherwise included within categories (ii)-(x));
20	Food and kindred products
21	Tobacco products
22	Textile mill products
23	Apparel and other finished products made from fabrics and similar materials
2434 Wood kitchen cabinets
25 Furniture and fixtures
265 Paperboard containers and boxes
267 Misc. converted paper products
27 Printing, publishing, and allied industries
283 Drugs
285 Paints and allied products
30	Rubber and miscellaneous plastics products
31	Leather and leather products
Does not include 311
311 - Leather tanning and finishing
323 Products of purchased glass
34	Fabricated metal products, except machinery and transportation equipment
Does not include 3441
3441 - Fabricated structural metal
35	Industrial and commercial machinery and computer equipment
36	Electronic and other electrical equipment and components, except computer equipment
2 See discussion of 9th Circuit Court Decision on page 7.
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37	Transportation equipment
Does not include 373
373 • Ship and boat building and repairing
38	Measuring, analyzing, and controlling instruments: photographic, medical and optical
goods; watches and clocks
39	Miscellaneous manufacturing industries
4221	Farm product warehousing and storage
4222	Refrigerated warehousing and storage
4225 General warehousing and storage
Facilities in this category, and this category only, are exempt from current storm water permitting
requirements if there is no exposure to storm water of material handling equipment or activities, raw
materials, intermediate products, final products, waste materials, by-products, or industrial
machinery3.
TRANSPORTATION ACT OF 1991
The Transportation Act of 1991 provides an exemption from storm water permitting requirements for certain
industrial activities owned or operated by municipalities with a population of less than 100,000. Such
municipalities must submit storm water discharge permit applications for only airports, powerplants, and
uncontrolled sanitary landfills that they own or operate. The Transportation Act defines "uncontrolled sanitary
landfill" as a landfill or open dump, whether in operation or closed, that does not meet the requirements for
run-on and run-off controls established pursuant to subtitle D of the Solid Waste Disposal Act. The
permitting authority (EPA or the State) may designate other municipally owned or operated industrial facilities
for permitting on a case-by-case basis.
9th CIRCUIT COURT DECISION
The 9th Circuit United States Court of Appeals' opinion in NRDC v. EPA (June 4, 1992) invalidated and
remanded for further proceedings two regulatory exemptions from the definition of "storm water discharges
associated with industrial activity": (1) the exemption for construction sites disturbing less than 5 acres of
land (category x), and (2) the exemption of certain "light" manufacturing facilities without exposure of
materials and activities to storm water (category xi). In response to these two remands, the Agency intends
to conduct further rulemaking proceedings on construction activities under 5 acres and light industry without
exposure as ordered by the Court. EPA will not require permit applications for construction activities
disturbing less than 5 acres of land and category xi facilities without exposure until further rulemaking is
completed.
WHAT IS CONSIDERED A POINT SOURCE
The intent of the following is to provide some clarification on the terms "point source" and "discharge" under
the storm water regulations. A point source is defined at 40 CFR 122.2 as "any discernible, confined, and
discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete
fissure, container, rolling stock, concentrated animal feeding operation, landfill leachate collection system,
vessel or other floating craft from which pollutants are or may be discharged. This term does not include
return flows from irrigated agriculture or agricultural storm water runoff." EPA notes that this definition would
encompass municipal separate storm sewers. In view of this comprehensive definition of point source, EPA
needs to clarify in this rulemaking only that a storm water discharge subject to NPDES regulation does not
include storm water that enters the waters of the United States via means other than a "point source."
3 See discussion of 9th Circuit Court Decision.
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As further discussed below, storm water from an industrial facility which enters and is subsequently
discharged through a municipal separate storm sewer is a discharge associated with industrial activity which
must be covered by an individual or general permit pursuant to today's rule (55 FR 47997, November 16,
1990).
EPA would also note that individual facilities have the burden of determining whether a permit application
should be submitted to address a point source discharge. Those unsure of the classification of storm water
flow from a facility, should file permit applications addressing the flow, or prior to submitting the application
consult permitting authorities for clarification.
EPA intends to embrace the broadest possible definition of point source consistent with the legislative intent
of the CWA and court interpretations to include any identifiable conveyance from which pollutants might enter
the waters of the United States. In most court cases interpreting the term "point source", the term has been
interpreted broadly. For example, the holding in Sierra Club v. Abston Construction Co.. Inc.. 620 F.2d 41
(5th Cir. 1980) indicates that changing the surface of land or establishing grading patterns on land will result
in a point source where the runoff from the site is ultimately discharged to waters of the United States. That
case holds:
Simple erosion over the material surface, resulting in the discharge of water and other materials into
navigable waters, does not constitute a point source discharge, absent some effort to change the
surface, to direct the water flow or otherwise impede its progress . . . Gravity flow, resulting in a
discharge into a navigable body of water, may be part of a point source discharge if the [discharger] at
least initially collected or channeled the water and other materials. A point source of pollution may
also be present where [dischargers] design spoil piles from discarded overburden such that, during
periods of precipitation, erosion of spoil pile walls results in discharges into a navigable body of water
by means of ditches, gullies and similar conveyances, even if the [dischargers] have done nothing
beyond the mere collection of rock and other materials . . . Nothing in the Act relieves [dischargers]
from liability simply because the operators did not actually construct those conveyances, so long as
they are reasonably likely to be the means by which pollutants are ultimately deposited into a
navigable body of water. Conveyances of pollution formed either as a result of natural erosion or by
material means, and which constitute a component of a . . . drainage system, may fit the statutory
definition and thereby subject the operators to liability under the Act." 620 F.2d at 45 (emphasis
added).
Under this approach, discharges of storm water resulting from structures which increase the imperviousness
of the ground which acts to collect runoff, with runoff being conveyed along the resulting drainage or grading
patterns, are point source discharges.
The entire thrust of the regulation is to control pollutants that enter receiving water from storm water
conveyances. It is these conveyances that will carry the largest volume of water and higher levels of
pollutants. The storm water permit application process and permit conditions will address circumstances and
discharges peculiar to individual facilities.
In summary, if storm water runoff can be traced from a definite source of pollution to waters of the United
States and the other criteria are met (e.g., meets the definition of associated with industrial activity), there is
a very good likelihood that a permit is required for that discharge of storm water.
WHAT ARE WATERS OF THE UNITED STATES
Waters which are (or have been) used for interstate or foreign commerce including waters subject to the ebb
and flow of the tide; interstate waters, (including wetlands); lakes, rivers, streams (including intermittent
streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural
ponds, including tributaries to any of these waters. Also included are irrigation canals.
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Some State definitions of waters of the State also include roadside ditches and other rights of way. For a
complete definition of waters of the United States see 40 CFR 122.2.
Waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of the
Clean Water Act are not waters of the United States. This exclusion applies only to manmade bodies of
water which neither were originally created in waters of the United States nor resulted from the impoundment
of waters in the United States. Note: at 45 FR 48620, July 21, 1980, the Environmental Protection Agency
suspended until further notice in § 122.2, the last sentence, beginning "This exclusion applies ..."
STORM WATER
Storm water means storm water runoff, snow melt runoff, and surface runoff and drainage.
DISCHARGES THROUGH LARGE AND MEDIUM
MUNICIPAL SEPARATE STORM SEWER SYSTEMS
In addition to applying for a permit, an operator of a storm water discharge associated with industrial activity
which discharges through a large or medium municipal separate storm sewer system shall submit, to the
operator of the municipal separate storm sewer system receiving the discharge:
•	the name of the facility;
•	a contact person and phone number;
•	the location of the discharge;
•	a description, including Standard Industrial Classification, which best reflects the principal products
or services provided by each facility; and
•	any existing NPDES permit number.
In Colorado large and medium municipal separate storm sewer systems include Aurora, Denver, Colorado
Springs, Lakewood, and Pueblo. After the 1990 Census figures are final. Pueblo might be deleted and the
unincorporated portions of Arapahoe County added. In Utah the large and medium municipal separate storm
sewer systems consist of Salt Lake City and the unincorporated portions of Salt Lake County.
The City of Sioux Falls, South Dakota went over 100,000 population in the 1990 census and accordingly will
be added to the list medium municipal separate storm sewer systems in the near future. Facilities that
discharge storm water associated with industrial activity to a publicly owned storm sewer located within the
City of Sioux Falls should submit the above specified information to the City.
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