Maricopa County, AZ Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- C-O max lot coverage
- 35% of lot area
- C-S max lot coverage
- 25%, 5-acre minimum lot
- C-1/C-2/C-3 max lot coverage
- 60% of lot area
- Governing area
- Unincorporated Maricopa County only
- Roof overhang exclusion
- 2 ft primary / 1 ft accessory
- Appeal deadline
- 60 days, Board of Adjustment
- Governing section
- MCZO Section 504
Summary
In unincorporated Maricopa County, Zoning Ordinance Section 504 caps how much of a commercial lot a building can cover: 35% in C-O (Office), 25% in C-S (shopping centers on 5+ acre sites), and 60% in C-1, C-2, and C-3. Coverage counts every building footprint on the lot, with a narrow roof-overhang exclusion. The cap never reaches Phoenix, Scottsdale, Mesa, or any other incorporated city.
LOT COVERAGE: The percentage of the area of a lot that is occupied by all buildings. The first two (2) feet of roof overhang from the exterior walls of the primary building, and the first one (1) foot of roof overhang from the exterior walls of all accessory buildings, are not to be included in the lot coverage. ... Section 504. Commercial Zoning Districts Development Standards ... Lot Area Minimum (sq. ft.) 12,000 217,800 (5 acres) 6,000 6,000 6,000 ... Lot Coverage Maximum 35% 25% 60% 60% 60% ... Article 809.3. Yard, Coverage and Open Space: Any lot, after this Ordinance or amendments thereto become effective, shall not be reduced or diminished to cause the yards, lot coverage or other open spaces to be less than that required by this Ordinance ... An appeal to the Board of Adjustment ... shall be taken within a reasonable time, not to exceed 60 days ... by filing with the Zoning Inspector and with the Board of Adjustment a notice of appeal specifying the grounds thereof.
Full Breakdown
Section 504 of the Maricopa County Zoning Ordinance sets the lot coverage ceiling for every commercial zoning district in the unincorporated county: 35% in C-O, 25% in C-S (which also carries a 217,800-square-foot, five-acre minimum lot size for shopping centers), and 60% in C-1, C-2, and C-3. in C-1/C-2/C-3), lot width, and setbacks that interact with how much of the lot a structure can occupy. The Ordinance's Section 201 definition of "Lot Coverage" is the percentage of the lot area occupied by all buildings, but it excludes the first two feet of roof overhang on the primary building and the first one foot of overhang on accessory buildings from the calculation.
3 locks the standard in place going forward: no lot may be replatted, resurveyed, or otherwise altered in a way that pushes its yards, lot coverage, or open space below what Section 504 requires. Commercial projects built before September 22, 2008 are grandfathered out of the county's Plan of Development approval process tied to these standards, unless more than 75% of the value of the existing structures is later removed or destroyed, at which point full Plan of Development review, including the coverage limit, applies. 1, filing a notice of appeal with the Zoning Inspector within 60 days of the determination.
Violations & Fines
Exceeding the Section 504 coverage cap without a variance puts the excess floor area out of compliance: the Planning and Development Department can withhold or revoke permits and require the owner to remove or reduce the structure until the lot falls back within its 35%, 25%, or 60% limit, depending on district. Article 809.3 bars any lot split or resurvey that would push existing coverage below what the code already requires, protecting neighboring lots from creeping density. Disputes go to the Board of Adjustment, filed within 60 days.
Frequently Asked Questions
Does this lot coverage limit apply in Phoenix or Scottsdale?
What counts toward lot coverage in a commercial district?
Can I get an exception to build past the coverage cap?
Which commercial zoning district allows the most lot coverage?
Sources & Official References
Other rules in Maricopa County
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