Stormwater Management: Mesa vs Phoenix
How do stormwater management rules compare between Mesa, AZ and Phoenix, AZ?
Mesa and Phoenix have similar restriction levels.
Mesa, AZ
Maricopa County
Mesa regulates stormwater discharges under its National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permit. The city prohibits illicit discharges to the storm drain system under Mesa City Code Title 8, Chapter 5. Construction sites disturbing one or more acres must obtain an Arizona Pollutant Discharge Elimination System (AZPDES) permit and implement a Stormwater Pollution Prevention Plan (SWPPP).
View full Mesa rules →Phoenix, AZ
Maricopa County
Phoenix regulates stormwater through City Code Chapter 32C (Stormwater Quality Ordinance) and the Stormwater Policies and Standards Manual. Construction sites must prepare a stormwater pollution prevention plan (SWPPP) and conduct monthly inspections plus inspections within 24 hours of rainfall greater than 0.5 inches.
View full Phoenix rules →Key Facts Comparison
| Fact | Mesa | Phoenix |
|---|---|---|
| Code Section | Mesa City Code Title 8, Chapter 5 | - |
| Permit Type | MS4 NPDES permit | - |
| Construction Threshold | 1+ acre requires SWPPP | - |
| Illicit Discharge | Prohibited to storm drain system | - |
| Enforcement | Mesa Environmental Management | - |
| Code Chapter | - | Phoenix City Code Chapter 32C |
| SWPPP | - | Required for construction sites |
| Inspections | - | Monthly + within 24 hrs of ≥0.5" rain |
| Standards Manual | - | Stormwater Policies and Standards Manual |
| On-Site Retention | - | Required unless waived by manual |
Highlighted rows indicate differences between cities.
Mesa FAQ
Can I wash my car and let water flow into the street?
Residential car washing on pervious surfaces is generally acceptable. However, commercial car washing operations and any discharge containing pollutants (oil, soap in large quantities, chemicals) to the storm drain system is prohibited under Mesa City Code.
What is a SWPPP and when do I need one?
A Stormwater Pollution Prevention Plan is required for construction sites disturbing one or more acres. It outlines erosion and sediment controls, waste management practices, and inspection schedules to prevent pollutants from entering stormwater runoff.
Phoenix FAQ
What stormwater permits does Phoenix require?
Construction sites must submit a stormwater pollution prevention plan (SWPPP) with grading and drainage plans per Chapter 32A. The Stormwater Quality Ordinance (Chapter 32C) establishes discharge requirements. Monthly visual inspections are required.
Is on-site stormwater retention required?
Yes. Phoenix generally requires on-site retention of stormwater as part of grading and drainage plans, unless waived by the Stormwater Policies and Standards Manual criteria.
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