Arizona Statewide Rule

Arizona AZPDES Stormwater Permit Statewide Requirements

Heavy RestrictionsApplies statewide across Arizona (2026)

Key Facts

Statute: ARS 49-255 et seq.
Regulator: Arizona DEQ
Construction Threshold: One acre disturbed
Max Penalty: $25,000 per day

Last verified: September 5, 2026Source: Arizona State Legislature

Summary

Arizona regulates stormwater discharges through the AZPDES program under ARS Title 49, requiring permits for construction, industrial, and municipal stormwater statewide.

L. When developing a general permit for discharges of storm water from construction activity, the director shall provide for reduced control measures at sites that retain storm water in a manner that eliminates discharges from the site, except for the occurrence of an extreme event. Reduced control measures shall be available if all of the following conditions are met: 1. The nearest downstream receiving water is ephemeral and the construction site is a sufficient distance from a water warranting additional protection as described in the general permit. 2. The construction activity occurs on a site designed so that all storm water generated by disturbed areas of the site exclusive of public rights-of-way is directed to one or more retention basins that are designed to retain the runoff from an extreme event.

Source: Arizona State LegislatureView official code

Full Breakdown

ARS 49-255 et seq. authorizes the Arizona Department of Environmental Quality to administer the Arizona Pollutant Discharge Elimination System (AZPDES). Construction sites disturbing one or more acres must obtain coverage under the AZPDES Construction General Permit, prepare a Stormwater Pollution Prevention Plan, and install best management practices. Municipal Separate Storm Sewer Systems (MS4s) in larger cities operate under individual or general permits. Local stormwater ordinances may add controls but cannot replace state permit obligations.

Violations & Penalties

AZPDES violations carry civil penalties up to $25,000 per day per violation under ARS 49-262, plus potential criminal liability for knowing discharges and required corrective action.

Frequently Asked Questions

When does an Arizona construction site need an AZPDES stormwater permit?

Permit coverage is required when site grading or clearing will disturb one acre or more, or when smaller sites are part of a larger common plan of development that exceeds the one-acre threshold.

Do Arizona cities issue stormwater permits or ADEQ?

ADEQ issues the AZPDES permit and enforces statewide. Cities operating MS4s have their own permits and may require local grading permits, but the state discharge permit is mandatory and not delegable.

Sources

See something wrong?

Help us keep this page accurate. If you notice an error or outdated information, let us know.