Maricopa County, AZ Environmental Rules: Erosion Control (2026)
Key Facts
- Enforcing agency
- County Drainage Administrator
- Applies to
- Unincorporated Maricopa County only
- Engineer required
- For subdivisions, commercial, multi-family plans
- Clearance expires
- 180 days without substantial construction
- Renewal
- One 180-day extension allowed
Summary
Unincorporated Maricopa County requires a drainage clearance from the county Drainage Administrator before grading, building, or development work begins, enforced under MCZO Section 905.
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 adversely affect drainage as determined by the Drainage Administrator. Upon application, the Drainage Administrator may approve a renewal of an expired Drainage Clearance for an additional 180 days.
Full Breakdown
Before grading, building, or developing land in unincorporated Maricopa County, applicants must obtain a drainage clearance from the county's Drainage Administrator (the Director of Planning and Development or a designee). Subdivisions, master-planned developments, and commercial, industrial, and multi-family projects must submit a Grading & Drainage Plan and Drainage Report prepared, signed, and sealed by an Arizona-registered professional civil engineer. A drainage clearance issued with a building permit expires if substantial construction has not occurred within 180 days, though the Drainage Administrator may grant one 180-day renewal. Building without a required drainage clearance, or failing a final drainage inspection before certificate of occupancy, is a violation subject to enforcement.
Violations & Fines
Building or grading without a drainage clearance is a violation of MCZO Section 905; the county Drainage Administrator can order corrective action, and unauthorized fill or drainage obstruction may trigger removal at the owner's expense.
Frequently Asked Questions
Do I need a permit to grade my lot in unincorporated Maricopa County?
What happens if I build without a drainage clearance?
Does this apply inside Phoenix or Scottsdale?
Sources & Official References
Other rules in Maricopa County
Compare Maricopa County to another location·View the Arizona environmental rules overview
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