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Casa Grande, AZ Accessory Structures: ADU Rules (2026)

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Casa Grande, AZ, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Max ADU floor area: 75% of main house or 1,000 sq ft
Side yard setback: 5 ft or district minimum, less
Rear yard setback: 5 ft
Front/corner setback: not permitted in setback area
Eligible zones: UR, RR, SH, R-1, R-1A, R-2, R-4, PAD
ADUs per lot: one permitted ADU

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in Arizona under recent ADU streamlining laws. The Casa Grande, AZ rules below cover local size, height, and setback requirements.

Summary

In the City of Casa Grande, one accessory dwelling unit is a permitted use in the UR, RR, SH, R-1, R-1A, R-2, R-4 and Residential PAD zones, but its floor area is capped at 75% of the main house or 1,000 square feet, whichever is smaller, with its own setback rules.

One ADU shall be allowed as a permitted use within UR, RR, SH, R-1, R-1A, R-2, R-4, and Residential PAD zone districts with the following development standards: A. The gross floor area of an ADU is limited to 75% of the gross floor area of the single-family dwelling or 1,000 sq ft, whichever is less. B. Setbacks: 1. Shall not be located within a required front or corner side yard setback
2. Side yard setback – 5’ or the side yard setback in the zoning district, whichever is less
3. Rear yard setback – 5’ ... ... E. An accessory dwelling unit may not be built on top of a current or planned public utility easement unless the property owner receives written consent from any utility that is currently using the public utility easement or that may use the public utility easement in the future.

View official code

Full Breakdown

Casa Grande Municipal Code § 17.52.105 allows one ADU as a permitted use, meaning no rezoning or conditional use permit is required, within the UR, RR, SH, R-1, R-1A, R-2, R-4 and Residential PAD zone districts. The gross floor area of the ADU cannot exceed 75% of the primary single-family dwelling's gross floor area or 1,000 square feet, whichever figure is lower. The unit cannot sit inside a required front or corner side yard setback. Its side yard setback is five feet or the zoning district's standard side setback, whichever is less, and its rear yard setback is a flat five feet; eaves, overhangs and similar features may still encroach up to eighteen inches into those setbacks.

Building height must follow the standard for whichever single-family residential zone the ADU sits in. The ADU also counts toward the citywide accessory-structure limit in § 17.52.100(G): all accessory structures, including the ADU, located in the primary structure's required rear yard setback area together cannot exceed 25% of that area. Finally, an ADU cannot be built over a current or planned public utility easement unless the property owner gets written consent from every utility currently using, or that may in the future use, that easement.

Violations & Fines

Because ADUs are governed by Title 17 zoning, building or maintaining one outside these standards triggers § 17.72.050: a fine of not less than fifty dollars nor more than seven hundred fifty dollars, up to four months in jail, or both, as a Class 2 misdemeanor, with continuing violations fined per diem until the zoning administrator's correction order under § 17.72.020 is satisfied.

Frequently Asked Questions

How large can an ADU be in Casa Grande?

Section 17.52.105(A) caps an ADU's gross floor area at 75% of the primary single-family home's gross floor area or 1,000 square feet, whichever is less, so a larger main house does not unlock an unlimited ADU size.

Which zones allow an ADU in Casa Grande?

One ADU is a permitted use in the UR, RR, SH, R-1, R-1A, R-2, R-4 and Residential PAD zone districts under § 17.52.105. It is not listed as permitted in commercial or industrial districts.

Can I build an ADU over a utility easement?

No, unless you get written consent. Section 17.52.105(E) bars building an ADU on a current or planned public utility easement without written consent from any utility currently using it or that may use it in the future.

Sources & Official References

[1]Casa Grande Municipal Code § 17.52.105

Other rules in Casa Grande

Shed & Carport RulesSome Restrictions ADU Owner OccupancySignificant Restrictions Parking Rules: Loading ZonesSome Restrictions Parking Rules: Driveway RulesSome Restrictions Parking Rules: EV ChargingLight Restrictions Parking Rules: Abandoned VehiclesSome Restrictions Animal Ordinances: Pet LimitsSome Restrictions Animal Ordinances: Veterinary Clinic ZoningSignificant Restrictions

All Casa Grande rules

How Casa Grande compares: Easiest Cities to Build an ADU·Compare Casa Grande to another location·View the Arizona accessory structures overview

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