Can an ADU be Attached?

Now that Assembly Bill 670 is in effect, the rules in California regarding accessory dwelling units (ADUs) have changed. To infill urban areas with affordable housing and to prevent urban sprawl, homeowners are wondering how they can build an ADU on their property.

An ADU can either be attached or separate but will retain its own entrance, kitchen, and living space, all while sharing the utilities of the main house. These units can be attached via interior or exterior and involve many different configurations.

Read on to find out more about attached ADUs, including popular styles and concerns and considerations before building.

What Are ADUs and JADUs

An ADU is a secondary residence located on the same lot as the primary property. Sometimes these dwellings are called mother-in-law apartments or carriage houses. These homes can be either attached to the main house or completely separate, although they retain a separate entrance regardless.

A JADU, or junior accessory dwelling unit, is similar, but with some notable differences. An article for Maxable, author uncredited, titled “What is a JADU? (Junior Accessory Dwelling Unit),” discusses what makes a JADU unique.

A JADU cannot be larger than 500 square feet.
Its location should be within an existing home or attached garage. The home or garage can be expanded only up to 150 square feet to accommodate the JADU.
There must be a separate entrance, access to a bathroom, and an efficiency kitchen to qualify as a JADU.
The owner must also live on the same lot to legally rent out a JADU.
A JADU does not require the replacement of parking unless the garage is turned into a unit.

Why Is This Type of Housing Important to a Community?

Accessory dwellings have much to offer communities, as discussed by the AARP in their guide titled “The ABCs of ADUs.”

Homeowners might rely on the extra income that comes from accessory dwellings, or the extra space is needed for family members.
Furthermore, having access to affordable housing is essential for areas that lack the option to sprawl out further from an urban center.
Lastly, flexible, affordable housing is vital for communities.

Different Styles of Attached ADUs

There are plenty of options for homeowners to create beneficial, affordable living units for their community. Frequently, homeowners opt to have accessory units attached to their homes or garages.

Attached ADU

Attached accessory dwellings are additions that are added to the side or the back of a home.

For homeowners who do not wish to lose parts of their yard, adding a second story with an exterior entrance is another option.
For homeowners who do not want to add to their house, a garage is an option. However, they do not need to necessarily lose their garage parking for the convenience of an accessory dwelling. A single-story garage can be converted to a two-story by adding an addition to the top.

Interior ADU

An interior ADU is built from the existing space in a home.

Attic space might be converted to an accessory dwelling. However, there are unique considerations for roof vents, ceiling heights, and insulation when it comes to transforming an attic to an accessory dwelling.
Basements are popular choices for converting to an ADU. Basements are popular for conversion because of the space they provide. Also, because basements are below ground, the temperature stays moderate, which saves on utility costs overall. Plus, homeowners do not have to give up yard space to create an accessory dwelling.
If a garage is attached to a home, the garage itself can be turned into an accessory dwelling and is considered an interior accessory dwelling. These projects tend to get expensive; the addition of insulation and ensuring the garage is structurally sound enough to live in can be costly, although the added income from renting will balance out in the end.
Sometimes garages have underutilized lofts or second stories that can easily be converted to an accessory dwelling, as well.
Another option for an accessory dwelling is the conversion of a second floor. As homeowners age, the needs of the home change. Children grow up, and the requirements of elderly parents change. Converting the second story of a home creates a place for aging relatives or extra income for homeowners who find themselves with more home than they need.

Different Styles of JADUs

Junior accessory units are allowed in any zoning district that standard accessory units are permitted. These cannot be used as vacation rentals, but they can be rented long-term.

Often, JADUs are built into an existing bedroom. Homeowners will add an efficiency kitchen and an exterior door. Given the small size of this type of unit, the placement in an existing home gives the homeowner plenty of flexibility with where it is built.

What to Know Before You Build

Before building and renting an accessory unit, there are some legal considerations for homeowners. Even with new laws in place that loosen the restrictions on accessory units, there are still local development standards.

Are You Eligible?

Homeowners need to first verify their lot can house an ADU.

There are restrictions for setbacks, which is the distance between a structure and a property line.
Each lot has utilities that run underground. An attachment cannot make it so the city cannot access these utilities.
Homeowners also need to make sure there is not a maximum height for structures if they plan to build up.

Parking Problems

Some communities struggle with parking. This issue is one criticism of the new law.

When homeowners add housing to their property, the community must find a way to deal with all the extra traffic and the lack of parking spaces available.

However, the new laws encourage local officials to allow garages to be converted without requiring new parking to be accommodated. Typically, local zoning addresses parking, so it is helpful for homeowners to find out what is expected.

Existing Utility Connections

Accessory dwellings are not considered new residences because they connect to the primary home’s utilities. Homeowners still should evaluate their sewer, existing plumbing, and furnaces to ensure they are up to code and have the capacity to handle the additional demand.

Fire Regulations

Jurisdictions have different demands regarding fire sprinklers. Frequently new ADUs do not need to have fire sprinklers the way new builds do, but it is helpful to check with local fire officials. Plus, installing them when they are not required often helps homeowners save on insurance premiums.

To Conclude

The new law encouraging urban infill to create affordable housing for communities went into effect at the beginning of 2020. With this change, homeowners are evaluating how to create flexible living space in their existing homes or how to build on to create this space properly.

Homeowners might be motivated by wanting elderly family members to live close by, but with the added privacy of separate living spaces.

Homeowners may also wish to benefit from the extra income an accessory dwelling creates. As communities fill in with affordable housing, both renters and homeowners benefit financially. However, homeowners must understand that there are considerable building costs they will incur while building and may not make a profit for a while.

Before building an accessory dwelling, homeowners need to investigate their local laws that govern the details for building on to their homes to ensure standards are met.