Who needs a SWPPP in Arizona?
Any construction project that disturbs one acre or more — or is part of a larger common plan of development reaching one acre — needs a SWPPP under Arizona permit AZG2025-001.
Arizona runs its own delegated stormwater program. Operators obtain coverage from ADEQ under AZPDES Construction General Permit for Stormwater Discharges Associated with Construction Activity (2025 CGP) (AZG2025-001), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.
Arizona adds requirements worth flagging early: File the NOI (with latitude/longitude of each outfall to six decimal places) in the myDEQ portal before construction and pay the initial AZPDES fee under A.A.C. R18-14-109; annual fees are due on each anniversary of the authorization certificate until a NOT is filed (Parts 2.3–2.4); Erosivity waiver (small sites): an operator whose construction activities disturb between one and five acres may be eligible; construction activities that disturb five acres or greater, or less than five acres but are part of a common plan of development or sale, are not eligible. Low erosion potential is a rainfall erosivity factor R < 5 for the construction period (calculated in myDEQ); sites with outfalls within 1/4 mile upstream of a WOTUS impaired or not-attaining water, or an Outstanding Arizona Water, are not eligible; the waiver still requires filing in myDEQ but no SWPPP, and if work continues past the waiver end date a SWPPP and NOI are required (Part 1.6); Post the authorization number(s) near the main entrance with the statement “For stormwater complaints, please visit www.azdeq.gov.” in lettering 2 inches or greater, and keep the authorization certificate in the SWPPP (Part 6.7); Outfalls within 1/4 mile upstream of a WOTUS impaired, not-attaining, or Outstanding Arizona Water: inspection of the site at least every 7 calendar days (Part 4.2.3), stabilization within 7 calendar days of the most recent disturbance for areas within 50 feet of such a water (Part 3.4.1.a), a Sampling and Analysis Plan with analytical monitoring (DMR in myDEQ within 30 days of lab results; Part 7), and corrective action reports to ADEQ within 30 calendar days (Part 5.3.1); Within 1/4 mile upstream of an Outstanding Arizona Water, no non-stormwater may be discharged under the permit except from emergency fire-fighting, unless ADEQ specifically authorizes it (Part 1.3.2.c); Revise the SWPPP within 14 calendar days of an ADEQ notice of deficiency (Part 6.6); Provide the SWPPP to ADEQ within 7 calendar days of a public-records request (Part 6.7).
What the plan must contain
An Arizona SWPPPis the site's compliance binder — the document an inspector opens first. It documents:
- 1Site & project descriptionTotal and disturbed acreage, soils, slopes, and the sequence of construction.
- 2Receiving waters & discharge pointsWhere stormwater leaves the site and the waterbodies it reaches.
- 3Erosion & sediment control BMPsSilt fence, stabilized entrances, inlet protection, and stabilization measures.
- 4Inspection schedule & recordsDated, signed inspection logs and the corrective actions taken.
- 5Operator certificationThe SWPPP is signed by the legally responsible party before work begins.
Required and conditional BMPs
| Best management practice | Category | Status |
|---|---|---|
| Perimeter silt fence / sediment barrier | Sediment control | Required |
| Stabilized construction entrance | Tracking control | Required |
| Storm drain inlet protection | Sediment control | Required |
| Soil stabilization (seeding, mulch, blankets) | Erosion control | Required |
| Concrete washout containment | Good housekeeping | Required |
| Sediment basin or trap | Sediment control | Conditional |
| Dewatering / turbidity controls | Pollution prevention | Conditional |
Filing your Notice of Intent
Submit the Notice of Intent (or erosivity waiver) and pay the fee in ADEQ’s myDEQ permitting portal; all NOIs, SWPPPs, NOTs, and DMRs are submitted electronically in myDEQ, and other correspondence (e.g., corrective action forms) to AZPDES@azdeq.gov.
A Notice of Termination closes coverage once the site reaches final stabilization. Keeping the SWPPP and its inspection records on site is what keeps a project clear of stop-work orders.
Inspection requirements
The permit allows 2 inspection schedules; the operator follows one and records the choice in this plan: (a) 7-day schedule — inspect at least once every 7 calendar days (a minimum of once within seven calendar days, but not within 5 calendar days of the previous inspection) (AZG2025-001 Part 4.2.1.a); or (b) 14-day schedule with storm inspections — inspect at least once every 14 calendar days and within 24 hours of the occurrence of a storm producing 0.5 inch of rain or more in 24 hours (a minimum of once within 14 calendar days, but not within 10 calendar days of the previous inspection; for a storm continuing over several days, inspect within 24 hours after each occurrence of 0.5 inch of rain within 24 hours, throughout the remainder of the storm, including when several smaller storms accumulate more than 0.5 inch in 24 hours) (AZG2025-001 Parts 4.2.1.b and 4.2.2.c). The SWPPP documents the schedule chosen and the rain gauge or weather station used (AZG2025-001 Parts 4.2 and 4.2.2.a). Every inspection is dated and signed, and any failed control is corrected before the next storm.
| Trigger | Requirement |
|---|---|
| Routine — 7-day schedule | At least once every 7 calendar days (a minimum of once within seven calendar days, but not within 5 calendar days of the previous inspection) |
| Routine — 14-day schedule with storm inspections | At least once every 14 calendar days and within 24 hours of the occurrence of a storm producing 0.5 inch of rain or more in 24 hours (a minimum of once within 14 calendar days, but not within 10 calendar days of the previous inspection; for a storm continuing over several days, inspect within 24 hours after each occurrence of 0.5 inch of rain within 24 hours, throughout the remainder of the storm, including when several smaller storms accumulate more than 0.5 inch in 24 hours) |
How Arizona differs from the federal permit
| Arizona | Federal (EPA) | |
|---|---|---|
| Authority | ADEQ | U.S. EPA |
| Permit | AZG2025-001 | EPA CGP |
| Disturbance threshold | 1 acre | 1 acre |
| Plan name | SWPPP | SWPPP |
Because Arizona administers its own program, the federal EPA Construction General Permit does not apply directly here — the state permit governs. Sites inside a regulated municipal storm sewer system may carry additional local ordinance requirements on top of the state permit.
Frequently asked questions
Does Arizona require an engineer to prepare the SWPPP?+–
No. Arizona does not require a licensed PE stamp on a construction SWPPP statewide. The operator certifies the plan; engineer review is optional for complex sites.
What is the disturbance threshold in Arizona?+–
One acre — including sites under an acre that are part of a larger common plan of development totaling one acre or more.
How often must inspections happen in Arizona?+–
The permit allows 2 inspection schedules; the operator follows one and records the choice in this plan: (a) 7-day schedule — inspect at least once every 7 calendar days (a minimum of once within seven calendar days, but not within 5 calendar days of the previous inspection) (AZG2025-001 Part 4.2.1.a); or (b) 14-day schedule with storm inspections — inspect at least once every 14 calendar days and within 24 hours of the occurrence of a storm producing 0.5 inch of rain or more in 24 hours (a minimum of once within 14 calendar days, but not within 10 calendar days of the previous inspection; for a storm continuing over several days, inspect within 24 hours after each occurrence of 0.5 inch of rain within 24 hours, throughout the remainder of the storm, including when several smaller storms accumulate more than 0.5 inch in 24 hours) (AZG2025-001 Parts 4.2.1.b and 4.2.2.c). The SWPPP documents the schedule chosen and the rain gauge or weather station used (AZG2025-001 Parts 4.2 and 4.2.2.a).
Arizona-ready in minutes
Siltworks fills in your site data automatically, applies the Arizona requirements, and hands you an inspection-ready SWPPP — at 70–90% less than a consultant.
Requirements summarized from the publicly available AZPDES Construction General Permit for Stormwater Discharges Associated with Construction Activity (2025 CGP) (AZG2025-001) for planning purposes. The operator must review and certify every SWPPP before use.