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Stormwater Management Program

What is Stormwater?

Stormwater

Stormwater is naturally occurring precipitation, and while some stormwater soaks into the ground, much of it turns into runoff and can pick up pollutants like chemicals, automotive fluids, sediment, and litter as it flows over various surfaces. Runoff is channeled into the City of Avondale Municipal Separate Storm Sewer System (MS4). The MS4 has many parts, including catch basins, storm drains, curbs, inlets, scuppers, streets, gutters, retention basins, and any other City-owned structure that conveys stormwater to waters of the US.

It is important to understand that the MS4 is separate from the sanitary sewer system. The sanitary sewer transfers waste water from residences and businesses directly to the Water Reclaimation Facility for treatment.

In contrast, the MS4 has no treatment process and empties its unfiltered contents directly into basins, drainages, and bodies of water, where it eventually infiltrates into the groundwater. This is why preventing stormwater pollution is so important. Stormwater remains unfiltered as it makes its way through the MS4, so whatever goes down the storm drain can eventually end up in our water supply!

Typical pollutants found in stormwater include trash, fertilizers, household detergents, pool water, pet waste, sediment, gasoline and petroleum products, and hazardous chemicals.

Some non-stormwater discharges are allowed to the MS4, including water line flushing,landscape irrigation, discharge from potable water sources, foundation drains, air conditioning condensation, irrigation water, water from crawl space pumps,footing drains,lawn watering, resident car washing, and residential building wash water without detergents, among others. For more information, see Chapter 8, Article II of the City Municipal Code and the NPDES Small MS4 Permit.


Need to report an Illicit Discharge?

If you believe you see an illicit stormwater discharge in Avondale, we encourage you to report it!

Download the myAvondale mobile app

myAvondale mobile app
With the app you can quickly and easily submit reports of potential violations from your mobile device!

Contact Code Enforcement The City of Avondale Code Enforcement Division receives and responds to illicit stormwater discharge inquiries.


NPDES Permit

The City of Avondale participates in the National Pollution Discharge Elimination System (NPDES) program and maintains a stormwater permit through the Arizona Department of Environmental Quality to operate our MS4. The City’s NPDES permit is comprehensive and covers public education and outreach, good housekeeping, illicit stormwater discharges, and erosion and sediment control through Best Management Practices (BMPs). Implementing the permit helps the City prevent pollutants from entering the MS4, and ultimately our surface and groundwater.

There are six Minimum Control Measures (MCMs) that address the requirements of the Permit. These are outlined in the Stormwater Management Plan (SWMP) link to the left. The City has issued a Notice of Intent and adopted ordinances to address stormwater quality and quantity control in order to meet all federal and state regulations.

The City also operates a Well-Head Protection Program that helps prevent pollution from entering the MS4 from industrialNPDES logo sites such as automotive repair shops, gasoline stations, and metal finishers. These types of businesses are required to implement additional BMPs to ensure their pollutants do not go down storm drains or drywells.

Explore the links to your left to see the steps Avondale takes to keep stormwater clean and safe. You will also find actions you can take to prevent stormwater pollution yourself!