Maricopa County, AZ Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Minimum elevation
- 1 foot above highest grade within 10 ft
- Design storm
- 100-year peak runoff event
- Enforcing office
- Drainage Administrator, Planning & Development
- Exemption
- Non-livable buildings exempt
- Scope
- Unincorporated Maricopa County only
Summary
Unincorporated Maricopa County requires livable buildings to elevate finished floors at least one foot above the highest grade within ten feet of the foundation, with higher elevations required in undrained areas.
Finished floors of a livable building shall be elevated a minimum of one foot above the highest grade point within ten feet of the foundation of the building. In areas without established drainage infrastructure, the Drainage Administrator may require higher finished floor elevations, grading and drainage plans or an engineer's certification that the finished floor is safe from inundation during the 100-year peak runoff event to ensure safety.
Full Breakdown
The Maricopa County Zoning Ordinance sets a minimum finished-floor elevation for livable buildings: one foot above the highest grade point within ten feet of the building's foundation. Where drainage infrastructure isn't established, the Drainage Administrator can require higher elevations, grading and drainage plans, or an Arizona-licensed engineer's certification that the floor is safe from inundation during the 100-year peak runoff event. A lower elevation is allowed only if an engineer certifies it as the minimum necessary for that same 100-year safety standard. Non-livable buildings are exempt. The rule applies to unincorporated Maricopa County and sits within the county's drainage clearance review process administered by the Drainage Administrator.
Violations & Fines
Building without meeting the finished-floor elevation standard can hold up drainage clearance and final building inspection approval; the Drainage Administrator can require redesign, grading changes, or engineer certification before occupancy is approved.
Frequently Asked Questions
Does this apply inside Phoenix or Scottsdale?
Can I build lower than the 1-foot minimum?
Sources & Official References
Other rules in Maricopa County
Compare Maricopa County to another location·View the Arizona environmental rules overview
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