Environmental Rules in Maricopa County, AZ (2026)

5 county-level rules, plus city-specific rules for 10 cities in Maricopa County, Arizona.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Maricopa County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Stormwater Management

Grading and drainage plans need Drainage Administrator clearance before development in unincorporated Maricopa County; buildings 200 square feet or smaller and non-fixed pipe-rail fencing are exempt unless sited in a retention basin or drainage way.

Maricopa County Drainage & Stormwater Clearance Rules

Some Restrictions

Maricopa County Zoning Ordinance § 905.7.2

Provided no development is to be located within a retention basin or drainage way, a drainage clearance shall not be required for: (i) any building with an area of 200 square feet or less, or (ii) for pipe rail type fencing that is not permanently affixed to the ground.

Full ordinance details →Official source ↗

Erosion Control

Unincorporated Maricopa County requires a drainage clearance from the county Drainage Administrator before grading, building, or development work begins, enforced under MCZO Section 905.

Maricopa County Grading and Drainage Clearance

Some Restrictions

Maricopa County Zoning Ordinance § 905.7

Except as provided for in this Section, a drainage clearance shall be required for any application for entitlement or development. Unless substantial construction as approved by the Drainage Administrator has occurred within 180 days of issuance of a building permit, the drainage clearance may be declared null and void and removal may be ordered of any partially completed improvements which may...

Full ordinance details →Official source ↗

Flood Zones

The Flood Control District of Maricopa County (FCDMC) manages floodplain regulations for unincorporated areas and 14 municipalities. Development in FEMA-designated Special Flood Hazard Areas requires a Floodplain Use Permit. Desert flash flooding along washes and arroyos is the primary flood risk. Building in or near washes requires flood control approval. The county participates in the National Flood Insurance Program (NFIP).

Environmental: Flood Zones

Heavy Restrictions

FEMA Flood Map Service Center

FEMA Flood Map Service Center: Welcome! Looking for a Flood Map? Enter an address, a place, or longitude/latitude coordinates: Looking for more than just a current flood map? Visit Search All Products to access the full range of flood risk products for your community. About Flood Map Service Center The FEMA Flood Map Service Center (MSC) is the official public source for flood hazard informatio...

Full ordinance details →Official source ↗

Vehicle Idling Restrictions

Diesel trucks over 14,000 pounds are barred from idling more than five consecutive minutes anywhere in Maricopa County, with $100 first-offense and $300 repeat civil penalties under Ordinance P-21.

Maricopa County Vehicle Idling Time Limit

Some Restrictions

Maricopa County Ordinance P-21, § 3(A)-(B)

No owner or operator of a vehicle shall permit the engine of such vehicle to idle for more than five (5) consecutive minutes except as provided in Section 4 (Exemptions) of this ordinance. ... Any owner or operator who violates this ordinance is subject to a civil penalty of $100 for the first violation and $300 for a second or any subsequent violation.

Full ordinance details →Official source ↗

Flood Elevation Requirements

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.

Maricopa County Finished Floor Elevation

Some Restrictions

Maricopa County Zoning Ordinance § 905.7 (Design Parameters — Finished Floor Elevation)

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 durin...

Full ordinance details →Official source ↗