Arizona has made it easier to build and rent accessory dwelling units, commonly called casitas, but the laws do not turn every guest house into an income property. For buyers in Tucson, the gap between what a casita could earn and what it is legally allowed to do is where expensive assumptions begin, according to Tony Ray Baker, team leader at REMAX Fine Properties.
The laws matter to anyone weighing a Tucson purchase because casitas are increasingly viewed as a way to offset a mortgage, house aging parents, or give adult children a place to live while they save. Baker says buyers are calling more often about homes with rental-ready guest houses, and the research has to come before the offer.
Arizona passed House Bill 2720 in 2024, requiring larger cities to allow accessory dwelling units on residential lots where single-family homes are permitted. House Bill 2928, signed in 2025, extended similar requirements to counties. Baker sees the changes as a positive development for multigenerational housing and additional rental supply. State law also protects the ability to rent a qualifying unit on a long-term basis, so the old assumption that a casita in unincorporated Pima County cannot be rented is no longer generally accurate.
The laws set a framework, though. Setbacks, building codes, lot coverage, utility requirements, and permits still apply. Jurisdiction is a critical detail: a Tucson mailing address does not confirm a home sits inside the City of Tucson. Two nearly identical homes can fall under different jurisdictions, one in the city and one in unincorporated Pima County, and the rules for construction, permits, and short-term rentals can differ between them. That matters in the Catalina Foothills, where many homes with guest houses are in unincorporated county territory.
Pima County updated its accessory dwelling unit regulations in December 2025, allowing qualifying units to be used for long-term or short-term rentals, subject to applicable requirements. State law also lets local governments require the owner to live on the property when a newer unit is used as a short-term rental. Renting a casita for six months and advertising it for weekend stays are treated differently, and vacation rentals carry additional regulations.
A new law does not make every existing guest house eligible. Baker notes that older casitas were often built under different rules, and some were approved only for specific uses. Others carry permitting or construction issues that surface only when someone investigates. Homeowners associations add another layer, because private deed restrictions and governing documents can limit rentals, modifications, parking, and how accessory structures are used, even when state law and local zoning allow the use.
Baker starts with the buyer's goal: long-term rental income, a vacation rental, housing for family, or flexible space. Each points toward different properties. From there, the sequence is to confirm whether the home is in the City of Tucson or unincorporated Pima County, verify the casita was legally built and approved for its intended use, and review rental requirements and HOA documents. If rental income is part of the financial plan, the numbers need the same scrutiny: realistic rental rates, vacancy, insurance, maintenance, utilities, and taxes. A legal rental is not automatically a profitable one.
"I don't want my clients discovering what they can't do with a property after they own it," Baker says. "I want them to know before they write the offer." As more casitas appear in Tucson listings, the details behind each one will matter as much as the structure itself.
