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NPDES Permits and Stormwater

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Clogged storm drain Photo courtesy of the City of Palo Alto, CA.
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Stormwater Program

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The 1987 Water Quality Act (WQA) added section 402 (p) to the Clean Water Act, requiring that EPA issue National Pollutant Discharge Elimination System (NPDES) permits for the following five categories of stormwater discharges:

Program Audits

Program Audits are being conducted to determine compliance and status of MS4 permitting. See the MS4 Program Audit Reports.

Stormwater Program, Phase I

The five categories listed above are generally referred to as Phase I of the stormwater program. On November 16, 1990, as a first step in carrying out the requirements of the 1987 WQA, EPA promulgated final regulations (40 CFR 122.26) for stormwater discharges from MS4s serving a population over 100,000, and for storm water discharges associated with industrial activity (55 Fed. Reg. 47990). The Phase I industrial stormwater program requires permitting for construction sites which disturb five or more acres and for numerous types of industrial facilities which are identified in the regulations by standard industrial classification (SIC) Exiting EPA (disclaimer) code or narrative description.

Additional background information on the stormwater program and numerous guidance documents may be found at EPA's national stormwater Web site. Copies of stormwater program materials may also be obtained by from EPA's Office of Water Resource Center at (202) 566-1729.

Stormwater Program, Phase II

The stormwater program also includes a Phase II, which addresses discharges not covered by Phase I. U.S. EPA issued final Phase II regulations on December 8, 1999 (64 Fed. Reg. 68722). These regulations require stormwater permits by March 10, 2003 for numerous small MS4s, construction sites of one to five acres, and industrial facilities owned or operated by small MS4s which were previously exempted under the Intermodal Surface Transportation Efficiency Act.

No Exposure Exemption

The Phase II regulations also modified the Phase I regulations to provide an exemption from stormwater permitting for industrial facilities within the categories described at 40 CFR 122.26(b)(14)(i)-(ix) which have no exposure of industrial materials and activities to stormwater. Facilities claiming the exemption must submit a no exposure certification to the permitting authority once every five years (see also no exposure certification guidance). The Phase II regulations retain the no exposure exemption for "light" industrial facilities listed in the Phase I regulations at 40 CFR 122.26(b)(14)(xi). However, to claim the exemption, these facilities must now also submit the no exposure certification once every five years. Construction sites are ineligible for the no exposure exemption.

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Permitting Authority

The NPDES permit program, including stormwater permitting, has been delegated to the state in Arizona, California, Hawaii and Nevada (except for Indian lands in these states). EPA Region 9 is the permitting authority for Indian lands in Arizona, California and Nevada, and the Pacific Island Territories of Guam, American Samoa, the Commonwealth of the Northern Mariana Islands, Johnston Atoll, and Wake and Midway Islands. The vast majority of construction sites and industrial facilities within EPA Region 9 (and nationally) which discharge stormwater are permitted under general NPDES permits.

Permits Issued by EPA Region 9

Construction: For the areas where Region 9 is the permitting authority, one general permit has been issued for construction sites disturbing one or more acres (68 Fed. Reg. 39087, July 1, 2003). This permit is a reissuance of the previous permit which was issued on February 17, 1998.

Industrial: A second general permit (called the multi-sector general permit (MSGP))(65 Fed. Reg. 64746, October 30, 2000) has been issued for industrial facilities other than construction sites. The MSGP of October 30, 2000 is a reissuance of the original MSGP which was issued on September 29, 1995.

Construction and Industrial Permit Application: To apply for permit coverage under the construction general permit, a construction notice of intent (NOI) must be submitted to EPA. A similar industrial notice of intent is required for the MSGP. Permit coverage under the construction general permit may be terminated by submitting a construction notice of termination. Permit coverage under the MSGP may be terminated by submitting an industrial notice of termination.

Phase I MS4s for Arizona: In Arizona, MS4 permits have been issued by EPA Region 9 for the cities of Phoenix, Tempe, Mesa, Scottsdale, Glendale, Tucson, Pima County, and the Arizona Department of Transportation. These permits were issued prior to the State receiving authorization to administer the NPDES permit program on December 5, 2002.

Phase II Small MS4s: On September 18, 2002, Region 9 proposed a general permit for small MS4s in Arizona (including Indian lands), Indian lands in California and Nevada, and the U.S. Pacific Island territories. However, most of the small MS4s which were to be covered by the proposed permit are now under the jurisdiction of the State of Arizona. As a result, Region 9 decided not to issue its general permit; individual permits will be issued for small MS4s in the geographic areas remaining under the jurisdiction of Region 9.

Permits Issued by States

MS4s for AZ, CA, HI and NV: MS4 permits have been issued in the States of California, Hawaii and Nevada for all the large and medium MS4s covered by the Phase I stormwater program. General NPDES permits have also been issued for Phase II small MS4s in the States of Arizona, California, Hawaii and Nevada.

Construction/Industrial Permits for AZ, CA, HI, and NV: General NPDES permits have been issued in California, Hawaii and Nevada for stormwater discharges from construction sites disturbing one or more acres, and for Phase I industrial facilities. In Nevada, the State has also issued a separate general permit covering metal mining facilities. The State of Arizona has issued a general permit for construction sites disturbing one or more acres. In addition, the State of Arizona is now administering EPA’s MSGP for non-Indian lands in Arizona; when the MSGP was issued in 2000 (prior to the State receiving NPDES program authorization) it covered the entire State of Arizona.

Contact Information

EPA Region 9 Stormwater Program
Eugene Bromley (bromley.eugene@epa.gov)
(415) 972-3510

Or consult state stormwater contacts.

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Region 9 Stormwater Program Information Exiting EPA (disclaimer)

Additional information concerning state stormwater programs may be obtained from the following state agencies:

Regional Stormwater Information

In California Exiting EPA (disclaimer)

Municipal Stormwater Programs

In Arizona Exiting EPA (disclaimer)
In California Exiting EPA (disclaimer)

When Stormwater is Used to Recharge Ground Water

Discharges to ground water may be subject to local, state or federal requirements. Specifically, discharges via subsurface fluid distribution systems or other subsurface infiltrative devices may be subject to the federal underground injection control (UIC) requirements. The UIC program, authorized pursuant to the U.S. Safe Drinking Water Act, exists to prevent the endangerment of underground sources of drinking water. Stormwater injection wells need to be listed on state or federal inventory lists, and should not be used for the disposal of fluids other than storm water. To limit the potential for ground water contamination, EPA recommends that stormwater injection wells be constructed with spill catchment, and not be constructed to intersect the water table. For more information, see the list of EPA Regional UIC contacts.

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