ADU Knowledge
November 3, 2024

What does ADU stand for?

Argi Avetisyan
Argi Avetisyan
Gather ADU expert
What does ADU stand for?
Not sure where to start with your ADU project?

Schedule a free appointment with one of our ADU experts.

Book a call

An ADU stands for Accessory Dwelling Unit. It’s a secondary housing unit that is typically built on the same lot as a primary residence. These units are a way to add more living space without requiring additional land development, making them a popular option for homeowners seeking to create more room, accommodate extended family, or generate rental income. Here’s an in-depth exploration of what ADUs are, their types, benefits, and other key considerations.

What is an ADU?

An Accessory Dwelling Unit (ADU) is a small, independent residential dwelling unit located on the same lot as a single-family home. It’s a term used widely in zoning codes and city planning regulations to describe any additional living quarters that are not part of the main house but reside within the same property boundaries.

ADUs are known by various names depending on the region, such as granny flats, in-law units, backyard cottages, or carriage houses. They provide an excellent solution to housing shortages by creating additional living spaces without expanding the footprint of residential developments.

Types of ADUs

Types of ADUs

ADUs come in different forms, and the most common types include:

  1. Detached ADU: This type is separate from the main house. It's a completely standalone structure, like a small house built in the backyard. Detached ADUs often have their own foundation, utilities, and can be designed to suit the specific needs of the homeowner.
  2. Attached ADU: This type is attached to the primary residence but has its own separate entrance. It may share a wall with the main house, but it is still an independent living space, usually complete with its own kitchen, bathroom, and living area.
  3. Garage Conversion ADU: In many cases, an existing garage can be converted into an ADU. This is one of the more cost-effective ways to add an ADU, as the structure already exists, and the conversion typically involves interior remodeling.
  4. Basement or Attic Conversion ADU: Similar to garage conversions, basements or attics of existing homes can be repurposed into ADUs. These conversions allow homeowners to make better use of existing space without expanding the home’s footprint.
  5. Junior ADU (JADU): JADUs are smaller than typical ADUs, often under 500 square feet. They are usually created by converting a portion of the existing home, such as turning a large bedroom or garage into a small independent unit. These are particularly useful for homeowners who need smaller, simpler units.

Benefits of ADUs

ADUs offer numerous benefits to both homeowners and the broader community. Here are some key advantages:

1. Affordable Housing Option

ADUs are often seen as a solution to the housing affordability crisis, especially in areas with high property values. They allow for the creation of additional housing units without the need for extensive new infrastructure or land development. This makes them much more cost-effective to build compared to standalone homes or apartment buildings.

2. Rental Income

One of the biggest draws for homeowners is the potential for rental income. By building or converting an ADU, homeowners can rent out the space and generate a steady stream of income. In high-demand areas, the rent from an ADU can significantly offset mortgage payments or provide a source of supplemental income.

3. Multigenerational Living

ADUs are perfect for families looking to accommodate multiple generations under one roof. For example, aging parents can live in a backyard ADU while still maintaining a degree of independence. Alternatively, young adults or grown children who are not yet financially independent can use ADUs as a stepping stone towards homeownership without the high costs associated with renting elsewhere.

4. Increased Property Value

Building an ADU can significantly increase the value of a property. Real estate buyers often see the potential for rental income or additional living space as a valuable asset. In regions where housing shortages are prevalent, properties with ADUs can command higher prices in the market.

5. Sustainability and Efficient Use of Land

ADUs make efficient use of existing land. Instead of expanding urban sprawl and consuming more green space, ADUs are built on already developed lots. They also contribute to the "infill housing" movement, where new housing is built within the existing urban fabric, making cities denser and more walkable.

6. Customizable Living Space

Homeowners can design ADUs to fit their specific needs. Whether they’re looking for a home office, a space for guests, or a small rental unit, ADUs can be tailored to serve a wide range of purposes. This flexibility makes them highly attractive to homeowners who want additional space but have different priorities.

ADU Regulations and Zoning

gatheradu

While ADUs offer many benefits, they are subject to local zoning laws and regulations. These rules can vary significantly depending on the city or region. Some common regulations that affect ADU construction include:

  • Size Limits: Many jurisdictions set limits on the size of ADUs. For example, an ADU might be restricted to a certain percentage of the size of the primary home, or it may have a maximum square footage, typically ranging from 600 to 1,200 square feet.
  • Parking Requirements: Some cities require homeowners to provide additional parking when building an ADU, although many have relaxed these rules in recent years, particularly in urban areas with access to public transportation.
  • Setback Rules: ADUs often have to adhere to setback requirements, meaning they must be built a certain distance away from property lines, neighboring homes, and other structures.
  • Occupancy Rules: Some jurisdictions require that either the ADU or the primary residence must be owner-occupied, meaning the homeowner cannot rent out both units. This is intended to prevent absentee landlords from developing properties purely for profit.
  • Permit Process: Building an ADU typically requires obtaining permits from local authorities. This process can involve submitting architectural plans, going through inspections, and complying with safety and building codes.

Challenges of Building an ADU

Despite the many benefits, there are some challenges involved in constructing an ADU.

1. High Upfront Costs

Although ADUs are more affordable than building new homes, the upfront costs can still be significant. Construction costs vary widely depending on the location, the type of ADU, and the materials used. On average, a detached ADU can cost between $100,000 and $300,000 to build, while conversions (like garages or basements) tend to be more affordable.

2. Financing

Securing financing for an ADU can be tricky. Not all banks offer specific ADU loans, and homeowners may have to rely on home equity loans, lines of credit, or personal savings to fund the project. However, as ADUs become more popular, some lenders are beginning to offer specialized ADU financing options.

3. Complex Regulations

Navigating the regulatory landscape can be complex, especially in cities with strict zoning laws. Homeowners need to research their local regulations thoroughly and may need to hire architects or contractors who specialize in ADU construction to ensure compliance.

4. Construction Disruptions

Building an ADU can be disruptive, especially in urban areas with limited space. Construction noise, limited access to the property, and temporary changes in the living environment can cause inconveniences to the homeowner and neighbors.

Final Thoughts

ADUs offer a versatile, cost-effective way to add housing in urban and suburban areas. Whether they’re used for rental income, multigenerational living, or simply as extra space, ADUs provide solutions to many of the housing challenges faced today. However, homeowners must carefully navigate the regulatory environment, secure financing, and consider the potential costs before embarking on an ADU project.

Understanding what an ADU stands for, and how it can benefit you, is crucial if you're looking to expand your home’s footprint or generate extra income. ADUs are changing the way people think about housing and are set to play an increasingly important role in the future of real estate development.

Popular ADU Floorplans

Malibu
Malibu
1,000 SQFT
3 Bed / 2 Bath
Monterey
Monterey
750 SQFT
2 Bed / 1 Bath
Topanga
Topanga
600 SQFT
1 Bed / 1 Bath
Carmel
Carmel
500 SQFT
1 Bed / 1 Bath
Sonoma
Sonoma
400 SQFT
1 Bed / 1 Bath
Marina
Marina
300 SQFT
Studio / 1 bath
gather adu team

Not sure where to start with your ADU project?

Close

Not sure where to start with your ADU project?

Book a free call