What Is an Accessory Dwelling Unit?

As housing costs continue to rise, many homeowners are exploring creative ways to maximize their property's value and functionality. One increasingly popular option is building an accessory dwelling unit (ADU). Whether you're looking to create space for family members, generate rental income, or increase your home's value, an ADU may offer a flexible solution.

If you're a homeowner in Tucson or Southern Arizona, understanding the benefits, requirements, and financing options for an ADU can help you determine whether it's the right investment for your property.

What Is an Accessory Dwelling Unit (ADU)?

An accessory dwelling unit, commonly known as an ADU, is a secondary residential living space located on the same property as a primary residence. ADUs are fully functional living quarters designed to operate independently from the main home.

You may also hear ADUs referred to as:

• Granny flats
• In-law suites
• Secondary suites
• Carriage houses
• Backyard cottages

Depending on local regulations, ADUs may be subject to zoning restrictions, permit requirements, and occupancy guidelines. Homeowners should always verify local building codes and zoning requirements before beginning construction.

Types of Accessory Dwelling Units

ADUs generally fall into two categories: detached and attached.

Detached ADUs

Detached ADUs are separate structures located on the same lot as the primary residence. Examples include:

• Tiny homes
• Backyard cottages
• Mobile or manufactured homes (where permitted)
• Converted garages
• Detached workshops or outbuildings

Detached units often provide greater privacy for both homeowners and occupants.

Attached ADUs

Attached ADUs share at least one wall with the primary residence but maintain a separate entrance and independent living space. Unlike a guest bedroom or finished basement, occupants must exit one residence to enter the other.

This arrangement can be ideal for homeowners who want to remain close to family members while maintaining separate living quarters.

Essential Features of an ADU

While designs vary, most ADUs must include:

• A living area
• A sleeping area
• A functioning kitchen
• A bathroom
• Independent utility access or connections
• Basic services such as electricity, water, and heating or cooling

An ADU does not need to mirror every feature of a traditional single-family home, but it should be capable of functioning as a separate residence.

Benefits of Building an ADU

Homeowners build ADUs for many different reasons. Some use them as long-term rental properties, while others create living space for aging parents, adult children, or guests.

Potential Rental Income

An ADU can provide a valuable source of rental income that may help offset mortgage expenses, property taxes, maintenance costs, or other household expenses.

Housing for Family Members

ADUs can offer a practical housing solution for aging parents, college-aged children, or extended family members who want independence while remaining close to loved ones.

Increased Property Value

In many markets, a properly permitted ADU may increase the overall value and marketability of a property.

Additional Housing Supply

ADUs can help address housing shortages by creating additional living spaces within existing neighborhoods.

Potential Drawbacks of an ADU

While ADUs offer many advantages, homeowners should also consider the potential challenges.

Zoning and Permit Requirements

Local municipalities often have specific rules governing ADU size, placement, parking requirements, and occupancy limits.

Construction Costs

Building or converting a structure into an ADU can require a significant upfront investment. Costs may include design, permitting, utility connections, site preparation, and construction.

Ongoing Utility and Maintenance Expenses

Property owners remain responsible for maintaining the ADU and may be responsible for some or all utility costs.

Refinancing Considerations

Unauthorized or non-permitted ADUs can complicate future mortgage transactions, including refinancing or selling the property. If you're considering a refinance in the future, it's important that all improvements comply with local regulations.

Planning Your ADU Project

Before beginning construction, take time to define your goals.

Ask yourself:

• Will the ADU be used for rental income?
• Is it intended for an aging parent or family member?
• Will accessibility features be needed?
• How much privacy do you want for occupants?
• What is your budget?

The answers can help determine whether an attached or detached ADU makes the most sense for your situation.

Financing an Accessory Dwelling Unit

Many homeowners use financing solutions to fund ADU construction or renovations.

Potential financing options may include:

• A cash-out refinance
• A home equity loan
• A home equity line of credit (HELOC)
• A renovation loan
• Other mortgage financing solutions depending on eligibility

Homeowners can also explore available local or state programs that may provide financial assistance for ADU development.

If you're considering financing options, The Polder Group can help you evaluate solutions that align with your goals and financial situation.

Learn more about available mortgage loan programs and financing options.

Building Your ADU

Once your plans and financing are in place, construction can begin.

Be sure to work with qualified contractors who understand:

• Local zoning requirements
• Building codes
• Permit processes
• Utility connections
• Site-specific restrictions

Experienced professionals can help ensure your project meets local regulations and avoids costly delays.

Renting Out Your ADU

After construction is complete, many homeowners choose to rent their ADU to generate additional income.

Finding Tenants

Popular places to advertise include:

• Rental websites
• Social media marketplaces
• Local colleges and universities
• Community organizations
• Personal referrals

Thorough tenant screening can help protect your investment and identify qualified renters.

Setting Rental Rates

Rental pricing will depend on several factors, including:

• Location
• Size
• Amenities
• Utility arrangements
• Market demand

Research comparable rental properties in your area to determine a competitive rental rate.

Managing the Property

One advantage of owning an ADU is convenience. Since the property is located on your lot, routine maintenance and repairs are often easier to manage than a separate rental property.

However, landlords remain responsible for maintaining the unit and complying with applicable landlord-tenant laws.

Is an ADU Right for You?

An accessory dwelling unit can provide flexibility, housing opportunities, and potential income while adding value to your property. Whether you're creating space for family members or exploring rental opportunities, careful planning and financing are key to a successful project.

If you're considering building an ADU in Tucson or Southern Arizona, The Polder Group at CrossCountry Mortgage can help you explore financing options that may support your goals. From renovation financing to cash-out refinance opportunities, our team is here to guide you through the process.

Ready to discuss your options? Visit our Contact Us page or learn more about our mortgage refinance solutions.

Frequently Asked Questions About ADUs

Does an ADU increase property value?

A properly permitted ADU may increase a property's value, though the impact varies based on location, market conditions, and the quality of the construction.

Can I finance an ADU with a refinance?

Depending on your equity position and qualifications, a cash-out refinance may be one option for funding ADU construction or renovations.

Do ADUs require permits?

In most cases, yes. Permit requirements vary by municipality and may include zoning approvals, inspections, and utility requirements.

Can I rent out my ADU?

Many homeowners use ADUs as long-term rental properties. However, local regulations may affect rental eligibility and occupancy requirements.

This article is for educational purposes only and does not constitute financial or mortgage advice. Loan programs, rates, and guidelines may change at any time. All loans are subject to credit approval and underwriting. For guidance tailored to your situation, consult a licensed mortgage professional.