Step 1: Applicability - do you need a permit?

Is my facility regulated by the industrial stormwater permit?

This step provides information to help facilities determine if they need industrial stormwater permit coverage. Any facility that is engaged in a Narrative Activity or a Primary SIC Code, as listed within PDF icon Appendix D of the Multi-Sector General Permit, or within the table below, needs to apply for permit coverage or certify for No Exposure.

Step 1a: Review the SIC codes/Narrative activities that require coverage

  • See Appendix D for entire list of SIC codes and Narrative Activities

Step 1b: Read sector/industry-specific fact sheets

Have a specific question or situation regarding applicability? Check out these guidance documents:

Step 1c: Determine your Primary SIC code

How do I know what my SIC code(s) or Narrative Activities are?

Businesses are designated by their SIC code(s) or by Narrative Activities, often for Commerce/Revenue purposes. One way to determine what SIC codes and Narrative Activities are applicable to your facility is to refer to your federal tax form-the codes are typically located on the upper left of the Schedule C or C-EZ for Sole Proprietors, Form 1065 for Partners, Form 1120 for C Corporations, or Form 1120-S for S Corporations. 

How do I look up a SIC codes? What if I have a NAICS code?

Step 1d: Determine if your industrial activities are regulated

Not authorized

  • Co-mingled wastewater & stormwater discharges: this discharge is considered wastewater and a Wastewater Discharge Permit may be required.

Not required

  • NPDES/SDS permit with stormwater requirements:  If your individual wastewater discharge permit or other water permit (general or individual) has stormwater requirements, you do not need to apply for the Multi-Sector General Permit.  That permit will be updated when it’s up for reissuance.
  • MNG49 Permit:  If 100% of your industrial stormwater activities can be covered by the MNG49 Nonmetallic Mining and Associated Activities Permit for sand, gravel, and concrete activities, you do not need to apply for the Multi-Sector General Permit.
  • No Narrative Activities or Primary SIC code:  If you do not conduct a regulated narrative activity or regulated Primary SIC code, no permit is required.


  • Wood mulch/animal bedding manufacturing are regulated under either Primary SIC code 2421 Sawmills and Planing Mills, General, 2429 Special Product Sawmills, Not Elsewhere Classified, or 2499 Wood Products, Not Elsewhere Classified, which are all regulated Primary SIC Codes.
  • SIC code 5153 (Grain and Field Beans: Establishments primarily engaged in buying and/or marketing grain (such as corn, wheat, oats, barley, and unpolished rice); dry beans; soybeans, and other inedible beans) is not a regulated Primary SIC code, but SIC code 4221 (Farm Product Warehousing and Storage: Establishments primarily engaged in the warehousing and storage of farm products) is a regulated Primary SIC code.

Does my Facility have construction sand and gravel, aggregate, hot mix asphalt and/or concrete activities?

Facilities with 100% of their industrial activities covered under the “Nonmetallic Mining and Associated Activities” Permit (MNG49) do not need to apply for the Multi-Sector General Permit. These activities include:

  • Construction sand and gravel mining areas (SIC code 1442) that discharge stormwater and/or pit dewatering wastewater, but no wash water;
  • Dimension stone, crushed and broken limestone, granite or stone mining and quarrying areas (SIC codes 1411, 1422, 1423 and 1429) that discharge stormwater only; OR,
  • Hot mix asphalt production areas (SIC code 2951) that discharge stormwater only.

The MNG49 Permit can cover multiple locations.   For more information or to apply for the MNG49 Permit, go to the Nonmetallic Mining and Associated Activities program page. If a facility has additional industrial activities beyond what are listed above, either obtain the Multi-Sector General Permit for the location that has additional activities (such as local trucking, landfill activities) or obtain the Multi-Sector General Permit for portions of the facility with these additional activities.

Grain Elevators versus Grain Storage: I own or operate a grain elevator. Do I need permit coverage?

Establishments primarily engaged in buying and/or marketing grain, or country grain elevators primarily engaged in buying or receiving grain from farmers (as well as terminal elevators and other merchants marketing grain) fall within SIC code 5153, and therefore do not need permit coverage. Establishments primarily engaged in the warehousing and storage of farm products fall within SIC code 4221, which is storage only. "Storage only" means facilities that are storing grain for other purposes (i.e., ethanol facilities and grain mills), and not going to the farmers or feed stores.

Step 1e: Review definitions and regulations

  • Narrative Activity means those industrial activities as defined by 40 CFR §122.26(b)(14)(i), (iv), (v), (vii) and (ix).
  • Primary Standard Industrial Classification (SIC) Code for the purposes of the industrial stormwater permit, is the SIC code associated with the industrial activity that generates the greatest revenue. If revenue data is not available, the owner/operator shall base the determination on the number of employees engaged in the industrial activity. If it is not possible to determine the primary SIC code using either of these two methods, the owner/operator shall base the determination on the SIC code with the greatest production. The industrial activity that generates the greatest revenue, employs the most personnel, or has the greatest production, is the industrial activity assigned the primary SIC code.

State/Federal Industrial Stormwater Regulations

Step 1f: Review the 29 sectors of industrial activity


Sector Description

SIC Codes

Sector A

Timber products

SIC codes: 2411, 2421, 2426, 2429, 2431-2439 (except 2434), 2441, 2448, 2449, 2451, 2452, 2491, 2493, 2499
Narrative activity: A4, Logging-discharges from wet decking storage areas

Sector B

Paper and Allied Products Manufacturing

SIC codes: 2611, 2621, 2631, 2652-2657, 2671-2679

Sector C

Chemical and Allied Products Manufacturing

SIC codes: 2812-2819, 2821-2824, 2833-2836, 2851, 2861- 2869, 2873-2879, 2891-2899, 3952
Narrative activity: C1, Runoff from phosphate fertilizer manufacturing facilities that comes into contact with any raw materials, finished product, by-products or waste products

Sector D

Asphalt Paving and Roofing Materials Manufactures and Lubricant Manufacturers

SIC codes: 2951, 2952, 2992, 2999
Narrative activity: D2, Stormwater runoff from asphalt emulsion facility

Sector E

Glass, Clay, Cement, Concrete, and Gypsum Product Manufacturing

SIC codes: 3211, 3221, 3229, 3231, 3241, 3251-3259, 3261-3269, 3271-3275, 3281, 3291-3299
Narrative activity: E3, Cement Manufacturing facility, material storage runoff

Sector F

Primary Metals

SIC codes: 3312-3317, 3321-3325, 3341, 3351-3357, 3363-3369, 3398, 3399

Sector G

Metal Mining (Ore Mining and Dressing)

SIC codes: 1011, 1021, 1031, 1041, 1044, 1061, 1081,1094, 1099

Sector H

Coal Mines and Coal Mining-Related Facilities

SIC codes: 1221-1241

Sector I

Oil and Gas Extraction and Refining

SIC codes: 1311, 1321, 1381-1389, 2911

Sector J

Mineral Mining and Dressing

SIC codes: 1411, 1422-1429, 1442, 1446, 1455, 1459, 1474-1479, 1481, 1499 

Sector K

Hazardous Waste Treatment Storage or Disposal Facilities

Narrative activities:
K1, Hazardous waste treatment/storage/disposal facility for discharges not subject to effluent limitations in 40 CFR pt. 445 subp. A
K2, Hazardous waste treatment/storage/disposal facility for discharges subject to effluent limitations in 40 CFR pt. 445 subp. A

Sector L

Landfills and Land Application Sites

Narrative activities:
L1, Municipal solid waste landfill areas closed in accordance with 40 CFR 258.60
L2, Open or closed non-hazardous waste landfill and land application site not discharging to surface water
L3, Landfill that discharges to surface waters stormwater that has directly contacted solid waste

Sector M

Automobile Salvage Yards

SIC Code: 5015

Sector N

Scrap Recycling and Waste Recycling Facilities

SIC Code: 5093

Sector O

Steam Electric Generating Facilities

Narrative activities:
O1, Coal fired and oil fired steam electric generating facility
O2, Nuclear, natural gas fired, and any other fuel source used for steam electric generation
O3, Runoff from coal storage piles at steam electric generating facility

Sector P

Land Transportation and Warehousing

SIC codes: 4011, 4013, 4111-4173, 4212-4231, 4311, 5171

Sector Q

Water Transportation

SIC codes: 4412-4499

Sector R

Ship and Boat Building and Repair Yards

SIC codes: 3731, 3732

Sector S

Air Transportation

SIC codes: 4512-4581

Narrative Activity:  S3: Existing and new primary airports with 1,000 or more annual jet departures that discharge wastewater associated with airfield pavement deicing that contains urea co-mingled with stormwater.

Sector T

Treatment Works

Narrative activity: T1, Treatment works with design flow of 1 million gallons per day or more or are required to have an approved pretreatment program under 40 CFR pt. 403

Sector U

Food and Kindred Products

SIC codes: 2041-2048, 2074-2079, 2011-2015, 2021-2026, 2032-2038, 2051-2053, 2061-2068,2082-2087, 2091-2099, 2111-2141

Sector V

Textile Mills, Apparel, and Other Fabric Products Manufacturing

SIC codes: 2211-2299, 2311- 2399, 3131-3199

Sector W

Furniture and Fixtures

SIC Codes: 2434, 2511-2599

Sector X

Printing and Publishing

SIC codes: 2711-2796

Sector Y

Rubber, Miscellaneous Plastic Products, and Miscellaneous Manufacturing Industries

SIC codes: 3011-3069, 3081-3089, 3931, 3942-3949, 3951-3955 (except 3952), 3961, 3965, 3991-3999

Sector Z

Leather Tanning and Finishing

SIC code: 3111

Sector AA

Fabricated Metal Products

SIC codes: 3411-3499, 3911-3915, 3479

Sector AB

Transportation Equipment, Industrial and Commercial Machinery

SIC codes: 3511-3599, (except 3571-3579), 3711-3799, (except 3731 and 3732)

Sector AC

Electronic and Electrical Equipment and Components, Photographic and Optical Goods

SIC codes: 3571-3579, 3612-3699, 3812-3873


Step 1g: Review additional guidance materials

Go to Step 2