Section 405 of the Water Quality Act of 1987 (WQA) added section 402(p) of the Clean Water Act (CWA), directed the United States Environmental Protection Agency (USEPA) to develop a phased approach to regulate storm water discharges under the National Pollutant Discharge Elimination System (NPDES). The USEPA published a final regulation in the Federal Register of this program on November 16, 1990, establishing permit application requirements for "storm water discharges associated with industrial activity." These regulations defined the term "storm water discharge associated with industrial activity" in a comprehensive manner to cover a wide variety of facilities as described in 40 CFR 122.26(b)(14)(x).

According to the November 16, 1990 final rule, facilities with a "storm water discharge associated with industrial activity" were required to apply for a storm water permit. The USEPA has defined “industrial activity” to include the following eleven categories:

  1. Facilities with effluent limitations
  2. Manufacturing
  3. Mineral, Metal, Oil and Gas
  4. Hazardous Waste, Treatment, or Disposal Facilities
  5. Landfills
  6. Recycling Facilities
  7. Steam Electric Plants
  8. Transportation Facilities
  9. Treatment Works
  10. Construction Activity
  11. Light Industrial Activity

Construction activities were identified as an industrial activity requiring permit coverage. However, these types of activities are regulated differently from the remaining categories of industrial activities, primarily since these activities vary from place-to-place and time-to-time (i.e. occur during different stages of property development). Industries requiring coverage under the categories above are sub-characterized by their standard industrial codes (SICs).

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USEPA Multi-Sector General Permit

The USEPA established a general permit to allow for coverage under the industrial NPDES requirements, known as the Multi-Sector General Permit, or MSGP. The MSGP was originally issued on September 29, 1995, and amended on February 9, 1996, February 20, 1996, September 24, 1996, August 7, 1998, and September 30, 1998. The final re-issuance of the MSGP appeared in the Federal Register on March 30, 2000 and went into effect on October 30, 2000. This first-phase of general permit coverage was commonly referred to as the EPA MSGP, or MSGP-2000.

A state run program for coverage under the MSGP was not granted to Arizona until 2002, two years after the issuance of the MSGP-2000. As such, all industrial activities in Arizona requiring coverage as detailed in 40 CFR 122.26(b)(14)(x) were required to apply for coverage under the MSGP-2000. The MSGP-2000 expired in October 2005, but was administratively continued.

The USEPA issued a new MSGP in February 2009 (EPA MSGP-2009). In Arizona, this permit applies only to Indian Country within Arizona. The EPA MSGP expires every five years, at which time either the current permit is administratively continued of a new general permit is issued.


EPA National Pollutant Discharge Elimination System (NPDES), EPA Multi-Sector General Permit (MSGP) website (special attention, see Appendix C, section C.9 EPA Region 9)

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ADEQ Multi-Sector General Permit

In 2002, the USEPA granted primacy of NPDES permitting to the Arizona Department of Environmental Quality (ADEQ) for all areas of Arizona excepting any such activities conducted on Indian Country. The ADEQ established the Arizona Pollutant Discharge Elimination Systems (AZPDES) requirements into the Arizona Revised Statute (ARS, Title 49, Chap 2, Article 3.1) and the Arizona Administrative Code (AAC, Title 18, Chapter 9, Article 9).

In June 2009, the ADEQ issued the draft Arizona Pollutant Discharge Elimination System General Permit for Discharge from Industrial Activities to Waters of the United States, commonly referred to as the ADEQ MSGP-2009. The ADEQ MSGP authorizes storm water discharges from industrial activities requiring permit coverage where those discharges have a potential to enter surface waters of the United States or a storm drain system. The ADEQ MSGP expires every five years, at which time either the current permit is administratively continued of a new general permit is issued. The ADEQ expects this permit to become effective by the end of 2009.

In general, the ADEQ MSGP requires operators of industrial activities that require permit coverage to submit a permit application (Notice of Intent, or NOI), develop a Storm Water Pollution Prevention Plan (SWPPP), and select, identify, implement, and maintain best management practices (BMPs) appropriate for site conditions.

STORM is in the process of developing an Industrial Operations Brochure that may be useful to regulated industrial site operators.


Arizona Revised Statutes, Title 49 - The Environment; Chapter 2 – Water Quality Control; Article 3.1 - Arizona Pollutant Discharge Elimination System Program

ADEQ Stormwater Permits

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Municipal Industrial Operation Requirements

While the ADEQ permit establishes minimum requirements for permitted industrial activities, regulated municipalities separate storm sewer system (MS4) operators may have established additional requirements and standards that must be met. To find out more information visit our Members & Sponsors webpage and select the community of interest.

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Helpful Links

STORM has provided links to ADEQ websites and EPA websites that offer information pertaining to stormwater permit coverage for industrial activities. Also included are links to the Arizona Department of Transportation (ADOT) and the Flood Control District of Maricopa County (FCDMC) since these organizations have prepared several documents related to sediment erosion and control stormwater BMPs that are referenced or adopted by many MS4 operators.

ADEQ Stormwater Permits Webpage (click the Mulit Sector link)

GPO Access Electronic Code of Federal Regulations (e-CFR) Title 40: Protection of Environment; Part 122.26 – USEPA Administered Permit Programs: The National Pollutant Discharge Elimination System; Subpart B—Permit Application and Special NPDES Program Requirements
Code of Federal Regulations Title 40: Protection of Environment; Part 122.26

U.S. Department of Labor, Occupational Safety & Health Administration; SIC Division Structure (of special interest, see SIC search link at bottom to search for SICs that apply to your facility’s operations)

USEPA National Pollutant Discharge Elimination System (NPDES); Post-Construction Stormwater Runoff Control website (useful information regarding structural BMPs and associated maintenance operations).

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