Pima County zoning codes are set out in Title 18 of the Pima County Code and sort unincorporated land into five base zone categories — rural, residential, transitional, business, and industrial — each with its own rules on what you can build, how you can use the property, and where structures must sit on the lot.1American Legal Publishing. Pima County Code – Title 18 Zoning Every parcel in the unincorporated county carries a base zone code, and that code is the starting point for any construction, business, or land-use decision.
The Five Base Zone Categories
Within each category, the specific zone controls density and intensity of use.
- Rural zones (RH and GR-1). Rural Homestead (RH) accommodates ranching, agriculture, and large-lot living. GR-1 Rural Residential is designed for orderly growth in semirural areas and allows limited commercial development that serves the surrounding community. Lots tend to be large, and livestock is generally allowed.
- Residential zones (CR-1 through CR-5). These run from single-family detached housing at CR-1, through mixed dwelling types at CR-4, up to multiple-residence developments like apartments at CR-5. Higher numbers allow greater density.
- Transitional zone (TR). TR buffers residential and commercial areas and permits low-intensity professional offices and multi-family housing.
- Business zones (CB-1 and CB-2). CB-1 is Local Business for neighborhood-scale shops and services. CB-2 is General Business for broader retail and commercial activity.
- Industrial zones (CI-1, CI-2, CI-3). CI-1 covers light manufacturing and warehousing, CI-2 handles general industrial uses, and CI-3 accommodates heavy industrial operations that produce more noise, odor, or traffic. All three are separated from residential neighborhoods.
Finding the Zoning on Your Property
The fastest way to identify your zone is the Pima County Parcel Search on the county’s Geographic Information Systems site. You can search by the nine-character parcel code (eight digits plus one alphanumeric character) or by street name.2Pima County Geographic Information Systems. Pima County – Parcel Search The GIS map overlays zone boundaries, and clicking a parcel returns its designation as an alphanumeric code like CR-3 or GR-1, which corresponds to a specific chapter of Title 18.
If a lender, buyer, or permitting agency needs written confirmation, request a Zoning Verification Letter from the Planning Division. Submit a letter describing exactly what you need — zoning classification, permitted uses, legal nonconforming status, or violation history — by email or in person at the Development Services Department. The county invoices for the letter and issues it after payment.3Pima County, AZ. Zoning Verification Letter
What the Zone Controls on Your Lot
Chapter 18.07 of the code lays out the physical rules for what you can build and where it can sit.4Pima County, Arizona Code of Ordinances. Pima County Code Chapter 18.07 – General Regulations and Exceptions Three numbers do most of the work: setbacks, building height, and lot coverage.
Setbacks are the minimum distances a structure must sit from property lines. In single-family residential zones, the standard front setback is typically 20 feet, and reducing it below that threshold requires a variance.5Pima County, AZ. Variance / Temporary Use and Interpretation Requests Side and rear setbacks depend on the specific zone and whether the lot borders a street. Denser zones generally allow narrower setbacks than rural ones.
Height limits cap how tall the structure can be. In the CR-5 Multiple Residence zone, the maximum is 34 feet.6American Legal Publishing. Pima County Code 18.29.030 Development Standards – General Rural zones with large lots may allow greater height, while zones adjacent to single-family neighborhoods are often more restrictive. Lot coverage — the percentage of your parcel that can be under roofed structures, including garages and guest houses — is spelled out chapter by chapter, and it ranges from modest percentages in rural zones to higher limits in urban and mixed-use zones.
Fences and Walls
Non-retaining walls and fences up to seven feet tall do not need a building permit. Anything taller, or any retaining wall, requires a permit and must comply with the setback rules for your zone.7Pima County, AZ. Do I Need a Permit? Near a commercial-to-residential boundary, screening rules under Chapter 18.73 may also apply.
Accessory Buildings
Detached garages, workshops, and storage buildings follow their own setback and height limits, usually stricter than the rules for the main house. In CR-4, accessory buildings are capped at 12 feet in height and can cover no more than five percent of the lot.8American Legal Publishing. Pima County Code 18.27.040 Development Standards – Accessory Buildings and Accessory Structures Rural zones are more generous. In the SR zone, accessory buildings can reach 24 feet and 1,500 square feet or 70 percent of the main building’s footprint, whichever is greater. Check the chapter for your specific zone before drawing up plans.
Overlays and Specific Plan Districts
Some properties carry a second layer of regulation on top of the base zone, and that layer can override what the base zone would otherwise allow.
The Hillside Development Overlay Zone (HD) is the most common example. It applies to parcels with steep terrain and requires development that minimizes visual and environmental impacts on hillsides.9American Legal Publishing. Pima County Code 18.61 – Hillside Development Overlay Zone A lot inside the HD overlay faces tighter grading limits, building envelope restrictions, and requirements for specialized engineering even if the base zone would otherwise allow a standard build. Floodplain management regulations, in a separate title of the code, can similarly restrict where on the lot a structure can go.
Large-scale developments sometimes operate under a Specific Plan (SP) district. An SP is a customized document that replaces the default Title 18 rules for a defined area, setting its own development standards, infrastructure plans, and permitted uses. The required contents — site analysis, maps, and written standards — are laid out in Chapter 18.90.10American Legal Publishing. Pima County Code 18.90.050 – Specific Plan Requirements If you buy inside an SP district, the Specific Plan controls your development rights, not the base zone code.
Guest Houses
Pima County allows one detached guest house per lot on residential or rural parcels of at least 4,000 square feet. A guest house can include a kitchen, but the county treats it as an extension of the main dwelling, not a separate rental unit. Occupants must be family members or nonpaying guests.11Pima County, AZ. Guest Houses
The restrictions are designed to keep the guest house from functioning as an independent apartment. It must be detached and at least three feet from the main residence, share the same driveway, and use the same utility meters. Separate electric or water service is not allowed. Maximum square footage is governed by the accessory building standards for your zone, so it depends on the zoning classification.
Home Occupations
Running a business from home is allowed in most zones, but the footprint is limited so neighborhoods stay residential in character. A home occupation can use no more than 25 percent of one floor of the residence, or up to 200 square feet in an accessory building. The permit stays with the property and does not need to be renewed.12Pima County, AZ. Home Occupations
The full performance standards, covering employees, signage, and customer traffic, are in Section 18.09.030. A business that outgrows those limits has to move to a commercially zoned property or pursue a rezoning.
Native Plant Preservation
Pima County’s desert landscape carries real legal protection tied directly to development. If your project will disturb more than 14,000 square feet on a lot larger than 36,000 square feet, you must prepare a Native Plant Preservation Plan under Chapter 18.72.13Pima County Development Services. Pima County Native Plant Preservation Set Aside Method Submittal Guidelines
Under the Set Aside method, 30 percent of the property must be permanently designated as Natural Open Space and left undisturbed, and that set-aside must include the land with the highest ecological value: washes, riparian habitat, and dense vegetation. Saguaros, ironwood trees, and Arizona safeguarded species outside the set-aside must be inventoried and either preserved in place, transplanted on-site, relocated off-site, or replaced through mitigation plantings. Hiring a biologist to inventory the lot is effectively mandatory, and the fencing and tagging requirements during construction add real expense.
Conditional Use Permits
Some uses are allowed in a zone only with special approval. A conditional use is typically a limited commercial activity that is generally compatible with the surrounding area but could affect neighbors — a daycare in a residential zone, for instance, or a cell tower in a commercial district.14Pima County, AZ. Conditional Use Application and Process
Each zone’s chapter in Title 18 lists which conditional uses it permits and classifies them as Type I, II, or III. Type I requires one public hearing. Types II and III require two. The county mails notice to property owners within 300 to 1,000 feet (depending on the zone) at least 15 days before the hearing. The hearing body can approve the request outright, approve it with conditions, deny it, or continue it for up to three months. Your submittal will need a completed application, a site plan, and a biological impact report.
Variances
A variance is not a zoning change. It is permission to deviate from a specific standard, like a setback or height limit, because the shape, size, or topography of the lot makes strict compliance unreasonable. The Board of Adjustment grants a variance only when the physical characteristics of the property would deprive the owner of privileges that similar properties in the same zone enjoy.15American Legal Publishing. Pima County Code of Ordinances – Section 18.93.030 Variances
Before the hearing, the county posts notice on the property and mails written notice to owners within 300 feet (up to 1,000 feet in certain zones) at least 15 days in advance. Neighbors can appear and testify for or against. The bar for approval is genuinely high. Wanting a bigger garage or a closer fence line is not enough. The hardship has to come from the land itself, not personal preference or cost savings.
Rezoning
If your intended use does not fit the current zoning, you can apply to change it. Rezoning requests must conform to the Pima County Comprehensive Plan, the county’s long-range land use blueprint. If the proposed zoning conflicts with the plan’s designation for your parcel, a Comprehensive Plan amendment has to come first.16Pima County, AZ. Comprehensive Plan Amendment Process and Submittal Guidelines
Applications go to the Development Services Department, either electronically or in person at the Planning Division.17Pima County. Rezoning Application and Submittal Guidelines The Planning and Zoning Commission holds a public hearing and issues a recommendation, but the Board of Supervisors has final say on approval or denial. Fees follow the county’s published schedule and vary by request type and acreage. The full process from application through hearing and decision typically takes several months.
Enforcement and Complaints
If a neighbor appears to be operating a business, building a structure, or using land in a way that violates the code, you can file a complaint through the Pima County Department of Environmental Quality. Before filing, the county recommends checking whether the property has an active construction permit by searching the address on the Development Services Customer Portal.18Pima County, AZ. Code Compliance A valid permit may mean the work is already approved. If no permit exists or the activity clearly falls outside the zone’s allowed uses, the complaint triggers an investigation by code compliance staff.
Enforcement runs both ways. Building without a permit, exceeding lot coverage, or breaking the home occupation rules puts the owner in the inspector’s path. Correcting a violation after the fact is almost always more expensive than getting it right the first time. Demolition, fines, and retroactive permitting fees add up quickly.