The Arizona Department of Transportation (ADOT) operates a municipal separate storm sewer system (MS4) that includes statewide highway operations on Interstates, US highways, and State Routes, as well as maintenance and associated support facilities. ADOT stormwater discharges are regulated by the Arizona Department of Environmental Quality as a Phase I MS4 under an individual permit. ADOT maintains an online library of resources, templates, manuals, and contact information. The website is intended to provide basic information for practitioners, industry, adjacent MS4s, and the general public. ADOT participates in STORM and other regional stormwater groups because it is important to exchange information regarding community resources, such as highways and environments, and communicate a standard message with respect to stormwater pollution.
