What States Allow ADU: Everything You Should Know

States that allow ADUs include California, Oregon, Maine, Connecticut, Washington, and New York along with other ADU-friendly states, each having its own rules. These states across the US have updated their zoning laws to permit Accessory Dwelling Units (ADUs). These smaller secondary homes on residential properties provide extra living space and help address housing shortages. Each of these states has its distinct regulations around ADU size, who can live in them, etc., to suit their housing needs.

In this article, you’ll learn about the ADU regulations in states where they are allowed, the benefits for homeowners, and practical details like design and financing.

What Are ADUs?

Accessory Dwelling Units, or ADUs, are small secondary homes that share the same lot as a main residence. These units provide additional living space separate from the main house, so homeowners can accommodate family members and renters or even use them as home offices. ADUs help increase housing options in cities and suburbs, making it easier to find affordable places to live.

The Perks of Accessory Dwelling Units

ADUs are becoming more common in many states because of the several benefits they offer. Here are some key advantages that come with these secondary units:

• Allows Building More Homes without New Land: ADUs can be constructed on existing properties without the need for extensive new land development, which can be time-consuming and costly. These smaller units help increase housing stock efficiently, whether you’re building a standalone or detached ADU, an attached ADU, or an interior ADU (like a converted garage or basement apartment).
• Supports Multigenerational Living: ADUs provide a great setup that allows families to stay close while maintaining privacy. This arrangement improves family connections and can also help with aging in place with the support of loved ones.
• Increases Density in the Right Way: ADUs allow cities to increase urban density without the downsides of overcrowding. By adding ADUs to existing homes, neighborhoods can have more housing without changing how they look.
• Offers Diverse Housing for Everyone: ADUs contribute to a variety of housing needs. They offer housing solutions for all, including young professionals seeking affordable urban spaces and seniors looking for downsized homes.
• Provides Economic Advantages for Homeowners: ADUs offer an economic advantage by providing affordable housing options in urban areas where the cost of living is typically high. Homeowners can generate rental income by renting out the extra space, which can help cover mortgages.

States that Allow ADUs

Recent statistics show there is a huge shortage of housing across the US. Thankfully, some states now allow homeowners to construct ADUs as a way to address this massive housing problem. Here are 6 states where you can add an ADU to your property.

California

California is one of the top states when it comes to being friendly toward ADUs. The state has laws in place to make it easier for homeowners to build these extra living spaces. Here are some important ADU regulations to keep in mind in California:

• Detached ADUs can be up to 1,200 square feet, while attached ADUs can be up to 50% the size of the main house.
• Many local cities and towns have relaxed the parking requirements for ADUs.
• The state has reduced red tape and timelines to make ADU approval quicker and simpler.

California has a statewide incentive (ADU Grant Program) to encourage affordable ADU development.

Oregon

In Oregon, ADU regulations focus on increasing housing options and making them affordable for residents. Some important ADU regulations in Oregon include:

• ADUs can be up to 70% the size of the main house, but detached units must not exceed 900 square feet.
• The state has relaxed parking rules for ADUs.
• Some cities do not require the property owner to live on the premises.

Maine

Maine passed its first ADU law in 2022, allowing interested homeowners in areas zoned for single-family homes to add accessory dwelling units. Some of the regulations regarding ADUs in the state include:

• ADUs must be at least 190 square feet.
• A lot can have either more than one ADU or one ADU for multi-family living.
• Cities can’t make homeowners add extra parking spots just for the ADU beyond what’s already required for the main house.

Connecticut

Connecticut state also has regulations that encourage homeowners to build ADUs. Important ADU regulations in Connecticut include:

• Single-family homes across the state are permitted to have ADUs, with certain exceptions related to environmental factors.
• ADUs are permitted by right, so city officials don’t need to give any special approval.

Keep in mind that many cities in the state have their own ADU regulations, so it’s important to check those if you live in Connecticut.

Washington

Washington has strong statewide ADU regulations, thanks to the recently passed House Bill 1337. The state creates a supportive environment for building ADUs with the following key regulations:

• Each lot can have up to two ADUs.
• The state has removed the rule requiring ADUs to have a specified number of parking spaces.
• Washington has removed the requirement that property owners must live on the premises to build an ADU.

New York

New York is addressing housing shortages by encouraging homeowners to build ADUs. The Plus One ADU Program is one way the state is doing this. The program offers low or no-interest loans as well as construction grants.

Additionally, the state has proposed legislation to support the development of ADUs, with regulations aimed at increasing housing options and affordability. While the state will set general guidelines, local governments will have major control over ADU regulations in New York.

Other ADU-Friendly States

Arizona

Arizona has state-level rules allowing ADUs, but cities can make their own additional regulations. The state requires larger cities to permit at least one ADU per single-family home, with size limits. However, some cities like Phoenix and Tucson have their own ADU policies.

Texas

Texas doesn’t have statewide ADU laws, so the rules are set by each city and county. This means that ADU rules can vary a lot from one part of the state to another. Some areas, like Austin, are pretty open to ADUs, while others are strict about them.

North Carolina

North Carolina allows ADUs, but the specific rules are determined locally by cities and counties. The regulations can vary significantly depending on where you live in the state. Homeowners need to check their local zoning codes to understand the ADU guidelines in their area.

Florida

Florida allows ADUs, but the regulations can vary significantly by locality. The state allows local governments to set ADU rules, which means requirements may be different across cities and counties.

Massachusetts

Massachusetts permits ADUs, but the regulations can vary greatly between different cities and towns. There are no statewide standards, so local jurisdictions can decide size limits, occupancy rules, and other ADU requirements. Some areas may require special permits for homeowners to build an ADU.

How to Add an Accessory Dwelling Unit to Your Property

Now that you know what states allow ADU, it’s time to see how to add these secondary units to your lot if you live in any of those ADU-friendly places.

1. Decide on an ADU Type. First, figure out what you want to use the ADU for: do you want to rent it out, house family or guests, or have a home office? This will help you decide the type and size of ADU that best suits your needs.
2. Come Up with a Budget. Get estimates from a few different local contractors with experience in ADU construction. This will help you figure out how much you’ll need for the project.
3. Finance Your ADU with RenoFi. Like many homeowners, you’ll probably need financing to complete your ADU project. Fortunately, there are several financing options you can explore, including refinancing your mortgage or doing a cash-out refinance. However, if you prefer more borrowing power, even if you don’t have substantial equity in your home, consider taking out a RenoFi home renovation loan. This option lets you access a significantly higher percentage of the after-renovation value of your home. Plus, you get to pay less in interest and lower fees.
4. Get Permits and Approval. Although you may live in a state that allows ADUs, you still need to get all the necessary permits before you start construction. It’s also important to make sure you build your ADU to comply with your area’s zoning code and regulations.
5. Work with a Professional. Consider hiring a design-build ADU company. This way, just one team will handle everything, including designing, permitting, and the physical construction. Besides, working with an expert ADU builder ensures your project meets local codes and regulations.
6. Begin the Construction. With all the permits in hand, you can start construction. After the construction phase, the unit must pass final inspections before you can use it for your desired purpose.

ADUs not only increase your home’s value after renovation but can also generate rental income. However, ADUs are costly. If you don’t have enough equity in your current home, funding ADU construction with a home equity loan is impossible.

For example, let’s say your current home value is $500,000, and your outstanding mortgage balance is $400,000. You are planning on adding an ADU and expect the value of your home to increase to $640,000. Your current loan-to-value ratio (LTV) is already at 80%, which means that most home equity loans are out of reach because that’s the maximum LTV they allow. So, your borrowing power using your current equity is $0.

RenoFi, on the other hand, would allow you to go as high as 150% LTV of your current value or 90% of your after renovation value, whichever is lower. So, in this example, while using a standard home equity loan results in your borrowing power being $0, a RenoFi loan allows you to borrow up to $176,000 by using the after renovation value of your home!

Get started with your RenoFi loan here

What to Consider When Planning Your ADU

Although specific ADU regulations vary between states and local governments, here are a few general factors to keep in mind when designing your accessory dwelling unit.

• Density and Size Constraints: The first step is to understand the density and size limitations of ADUs in your area. Local jurisdictions often set rules around the maximum square footage or how much of the lot can be occupied by the ADU in relation to the primary dwelling. Be sure your design plans fall within these constraints to avoid issues down the line.
• Structural Design: Pay close attention to height restrictions when deciding how tall the physical structure will be. ADUs may have lower maximum heights compared to the main house, so work closely with your contractor to ensure your design meets local building codes.
• Site Conditions: Take a close look at the specific site conditions where you plan to build the ADU. Factors like the slope of the land, drainage patterns, and soil quality can all impact the feasibility and cost of construction. Addressing these early on during the planning phase can save you headaches later.
• Parking Requirements: Many areas have relaxed parking rules for ADUs, especially if the unit is located near public transit. However, it’s still important to confirm if any off-street parking is required and make sure to incorporate that into your site plan.
• Access and Entry: It’s important to make sure there is safe, accessible entry to the ADU. This may involve adding a walkway from the street or strategically positioning the entrance for privacy. Basically, you should factor in how tenants and visitors will access the unit.
• Interior Design: When designing the unit’s interior, focus on maximizing the limited square footage. Built-in storage, space-saving furniture, and efficient appliances can help create a comfortable living space.
• Fire and Safety: ADUs need to follow strict fire and safety rules. For example, if the ADU is attached to the main house, there have to be special firewalls between them. And you’ll need features like smoke alarms and emergency exits to keep people safe. It’s important to plan for these fire and safety features when designing the ADU.
• Utilities: Running utilities such as water, sewer, electricity, and gas to the ADU takes some planning. You’ll need to consider where the main utility hookups are and the best way to connect the ADU. The location of the ADU on your property will depend on where it’s easiest and cheapest to bring in the utilities.

Let RenoFi Help You Bring Your ADU Vision to Reality

In addition to solving housing problems, ADUs offer more affordable places for people to live. Several states have modified their zoning codes and regulations to encourage homeowners to construct these smaller living spaces.

If you’re a homeowner in one of the states that allow ADUs but don’t have access to the funds you need to bring your ADU vision to reality, RenoFi can help. Our lending partners can work with you to provide a financing option that best suits your situation. Give us a call today at 855-736-6341. Let’s get your ADU project underway.

RenoFi loans are the smartest way to finance a home renovation project. Unlike traditional loans, which are based on your current home value or require you to refinance your primary mortgage and give up your low rate, RenoFi loans are based on the after renovation value of your home. This allows you to borrow, on average, 11x more, get a low monthly payment, and keep your low rate on your first mortgage.