Frequently Asked Questions

Stormwater Management

1. What is stormwater runoff?

Stormwater runoff occurs when precipitation from rain water flows over the ground. Impervious surfaces such as roads, sidewalks and streets don't allow rain water to be soaked into the ground. All the excess rain water which does not soak into the ground becomes stormwater runoff which discharges directly to rivers, washes and retention basins.

2. What is stormwater pollution?

As stormwater flows over impervious surfaces, it picks up and carries pollutants (such as oils, chemicals, pet waste, etc.) to the storm sewer system and ultimately our rivers, washes and retention basins.

3. What kinds of pollutants can be found in stormwater runoff?

Some common pollutants which may be present in stormwater are sediment, oil and grease, chemicals, nutrients, metals, bacteria, and garbage.

4. How can I help prevent stormwater pollution?

You can help prevent stormwater pollution by using Best Management Practices (BMPs) and good housekeeping measures. For example, using drip pans to collect leaks from vehicles, use the sanitary cleanout for disposing of pool water, pick up pet waste from yard and dispose of properly and properly dispose of household chemicals at your local hazardous waste collection event.

5. Does stormwater runoff go to a wastewater treatment plant?

Stormwater runoff does not go to a wastewater treatment plant. The City of Phoenix has two separate sewer systems, a sanitary sewer and storm drain sewer. The sanitary sewer takes wastes from toilets and sinks and delivers it to a wastewater treatment plant before discharging into the Salt River. The storm drain sewer takes all the stormwater runoff and goes untreated to rivers, washes and retention basins.

6. Who do I call/contact if I see someone dumping a pollutant into the storm drain?

If you see someone dumping or illegally discharging to the storm drain, please contact the City of Phoenix Stormwater Hotline at (602) 256-3190. The hotline is open 24 hours a day/7 days a week. All calls are anonymous. Please provide at a minimum where the location of the dumping/discharge occurred, date/time and any other additional information pertinent for the inspectors to follow-up with.

7. How do I legally drain/backwash my pool?

Under City Code Chapter 32C, pool water is not allowed to be discharged to the storm drains. Pool water should be discharged to your sanitary sewer cleanout or irrigation for plants. Please see How to Drain and Backwash Your Pool Legally for further information.

8. How/where can I properly dispose of household chemicals (e.g. motor oil, antifreeze, used batteries etc.)?

Do not dump any chemicals down the storm drains. You can dispose of your household chemicals at local hazardous waste pick-up locations. Please refer to the City's household hazardous waste event website for date and location.  Collections Events​ 

9. What can businesses do to help prevent stormwater pollution?

Your business can help prevent stormwater pollution by using Best Management Practices (BMPs) and good housekeeping measures. For example, sweeping, using covered storage areas for chemicals and materials and properly cleaning up and disposing of spilled materials.

10. Are there any City stormwater regulations for businesses and construction projects?

Businesses (which are deemed to have "potential to pollute") and certain construction projects (one-acre or more area of land disturbed) are required under City of Phoenix Code Chapter 32C to have and implement a Storm Water Management Plan (SWMP).