The U. S. Environmental Protection Agency (EPA) continues to be the permitting authority for all regulated stormwater discharges on Indian Lands. For more information on stormwater permitting on Indian Lands within Arizona, please visit: U.S. EPA Region 9 NPDES Stormwater Program . U.S. EPA also provides an electronic filing system for NOIs for their Construction General Permit. For more information, please see U.S. EPA Electronic Stormwater Notice of Intent (eNOI) .
U.S. EPA has estimated that about 30 percent of known pollution to our nation's waters is attributable to stormwater runoff. In 1987, Congress directed U.S. EPA to develop a regulatory program to address the stormwater problem. U.S. EPA issued regulations in 1990 authorizing the creation of a NPDES permitting system for stormwater discharges from a select group of industrial activities. The National Pollutant Discharge Elimination System (NPDES) is the administrative mechanism chosen for the stormwater permitting program. In Arizona, this program is called Arizona Pollutant Discharge Elimination System (AZPDES). An AZPDES permit is required for any point source discharge of pollutants to a water of the United States. Because stormwater runoff can transport pollutants to either a municipal separate storm sewer system or to a water of the United States, permits are required for those discharges.
Most stormwater discharges are permitted under various general permits. However, an individual permit is required when the general permit requirements do not accurately represent the activity at a facility and a permit is customized to the site.
An individual permit may be necessary if the Limitations of Coverage section of a general permit does not allow the facility's discharge to be covered within the general permit. It is the responsibility of every applicant to determine if any of the Limitations of Coverage apply to the facility seeking a general permit.
The following waterbodies (commonly referred to as the 303(d) list) were assessed by ADEQ as having impaired uses that require more than existing technology and permit controls to achieve or maintain water quality standards. The links below provide a list and map of these impaired waters.
Outstanding Arizona Waters (OAW)
ADEQ established, under A.A.C. R18-11-112, the following surface waters have been classified as outstanding Arizona waters.
Medium and Large Municipal Separate Storm Sewer Systems (Large MS4s)
There are 8 municipalities in Arizona that operate under individual stormwater permits. ADEQ has issued permits for all of the following Large MS4s:
Small Municipal Separate Storm Sewer Systems (Small MS4s)
The Phase II Regulations established by the U.S. EPA in 1999 required some municipalities to obtain a permit for their municipal stormwater discharges. These regulations stemmed from national studies and local findings within Arizona that showed runoff from urban areas greatly impairs stream ecology and the health of aquatic life (Federal Register/Vol.64, No.235). While many of the water courses in Arizona are ephemeral or intermittent, these national regulations still apply to Arizona.
Regulated municipalities include:
- Municipalities that are located wholly or partially in an urbanized area as defined by the 2000 US Census* (see 40 CFR 122.32(a)(1)). Regulated municipalities include five counties, 20 cities and 7 non-traditional municipalities. These municipalities were required to submit a Notice of Intent and Stormwater Management Program to ADEQ by March 10, 2003.
- Municipalities designated by ADEQ (see 40 CFR 122.32(a)(2)). These municipalities were required to submit their Notice of Intent and Stormwater Management Program to ADEQ by December 2003. Designated Municipalities include Camp Verde, Cottonwood, Douglas, Fountain Hills, Lake Havasu, Nogales, Sedona and Sierra Vista.
*The 2000 Census defined six urbanized areas within the state of Arizona. The urbanized areas were named for the central place in that region. Urbanized areas are geographic areas that have a population of 50,000 people and a density of 1000 people per square mile in the central place and adjacent densely populated area. Urbanized areas in Arizona, as determined by the US Census Bureau include:
Small MS4 General Permit (AZG2002-002)
There are 49 regulated small MS4s in Arizona that operate under Arizona's Small MS4 General Permit. In accordance with the Small MS4 General Permit, each MS4 is required to prepare and implement a Stormwater Management Program Plan (SWMP). The SWMP documents the control measures and Best Management Practices the MS4 must establish to meet the terms and conditions of the Small MS4 General permit. To review SWMPs, please contact the ADEQ Records Center at (602) 771-4380.
Small MS4 General Permit Forms
The following is a small list of the Small MS4s in Arizona, as established by the 2010 Census: