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Arizona Statewide Rule

Arizona Floodplain Management and County Flood Control Authority

Heavy RestrictionsApplies statewide across Arizona (2026)

Key Facts

Statute
ARS 48-3601 et seq.
Lead Agency
County flood control district
Floor Standard
NFIP minimums or stricter
State Coordinator
AZ Dept of Water Resources
Last verified: August 21, 2026Source: Arizona State Legislature

Summary

Arizona statutorily delegates floodplain regulation to counties and flood control districts, setting uniform minimum standards for development in mapped floodplains statewide.

Except as provided in section 48-3610, the board shall adopt and enforce regulations governing floodplains and floodplain management in its area of jurisdiction which shall include the following: 1. Regulations for all development of land, construction of residential, commercial or industrial structures or uses of any kind which may divert, retard or obstruct floodwater and threaten public health or safety or the general welfare.

Source: Arizona State LegislatureView official code

Full Breakdown

ARS Title 48 Chapter 21 (ARS 48-3601 et seq.) establishes floodplain management as a county responsibility and authorizes county flood control districts to adopt regulations meeting at least National Flood Insurance Program minimums. Cities may administer floodplain rules within their boundaries by intergovernmental agreement, but standards must equal or exceed county and state minimums. Building or grading in a regulatory floodway without a floodplain use permit is prohibited. The Arizona Department of Water Resources oversees state coordination.

Violations & Penalties

Unpermitted floodplain development can result in stop-work orders, civil penalties up to several hundred dollars per day, mandatory removal, and loss of NFIP eligibility for the community.

Frequently Asked Questions

Do I need a permit to build in an Arizona floodplain?
Yes. Any structure, fill, grading, or substantial improvement in a mapped Special Flood Hazard Area requires a floodplain use permit from the county flood control district or delegated city, regardless of building size.
Can Arizona cities adopt weaker floodplain rules than the county?
No. State law requires city floodplain standards to be at least as strict as county and NFIP minimums. Communities that adopt weaker rules risk losing federal flood insurance availability for their residents.

Sources

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