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What is Stormwater?

Surface Water Quality Protection

AZPDES Stormwater Permits

Revised On: Sept. 18, 2023 -  6:20 p.m.

What is Stormwater? 

Stormwater runoff from urban environments is generated from rain and snowmelt that flows over land or impervious surfaces, such as paved streets, parking lots, and building rooftops and does not soak into the ground. The runoff picks up pollutants like trash, chemicals, microbial contaminants, oils, and dirt/sediment. Unlike the water that is used in homes, which flows to a wastewater treatment facility, stormwater does not receive physical, biological, or chemical treatment before being discharged to the nearest waterway. This increases the impact on overall water quality and aquatic habitat.

To protect Arizona’s streams, rivers, and lakes, ADEQ issues Arizona Pollutant Discharge Elimination System (AZPDES) permits that require communities, construction companies, industries, and others, to use stormwater controls, known as best management practices (BMPs). These BMPs filter out pollutants and/or prevent pollution by controlling it at its source.

Stormwater Permits: