Junior ADU

No. Only one JADU may be created per lot zoned for single-family residences with an existing or proposed single-family residence. The JADU may be created within the walls of the proposed or existing single-family residence, including attached garages.

If there are multiple detached single-family residential units on one lot, there can only be one JADU.

SB 9 and State ADU Law are complementary. Both laws can be implemented in ways that result in developments with both “SB 9 Units” and ADUs. However, in no case does SB 9 require a local agency to allow more than four units on a single lot, in any combination of primary units and ADUs or JADUs.

For example, when a lot split has not occurred, the lot is eligible to receive a second primary unit on the lot under SB 9 and to receive up to two ADUs under State ADU Law. When a lot split occurs under SB 9, each lot is eligible for up to two units, including, for example, a primary unit and an ADU or JADU.

In the case that a lot owner both splits a lot and builds two primary units on each resulting lot under SB 9, State ADU Law is superseded (i.e., neither lot is entitled to an ADU or JADU); in all other cases, State ADU Law applies, up to SB 9’s four-unit cap.

Yes, a JADU is permitted in a half-plex. A half-plex consists of two primary dwelling units on separate lots that share a dividing wall. One JADU is permitted in each half-plex in areas zoned for single-family use. If two units are attached on a single lot (i.e., a duplex), the primary dwelling is considered multifamily and would not qualify for a JADU.

No, a JADU cannot be constructed on a multifamily site. JADUs may only be constructed on a site with a proposed or existing single-family dwelling in an area zoned for single-family residences.

No, JADUs are not allowed in accessory structures. The creation of a JADU must be within the single-family residence. “Enclosed uses” within the residence, such as attached garages, are eligible for JADU creation.

No. Only ADUs that are created from existing accessory structures are allowed to add up to 150 square feet “beyond the physical dimensions of the existing accessory structure” to provide for ingress or egress.

No setback shall be required for an ADU or JADU created within an existing living area or accessory structure.

JADUs are required to be within the walls of the primary dwelling but are not required to have an interior connection to the primary dwelling.

However, if the JADU does not include a separate bathroom, the JADU must include an interior entrance to the main living area.

No, inclusion of an existing bedroom is not required.

No. Local agencies may not require parking as a condition to permitting a JADU, even when the JADU is converted from an attached garage.

JADUs shall not be considered by a local agency, special district, or water corporation to be a new residential use for purposes of calculating connection fees or capacity charges for utilities, unless constructed concurrently with a new single-family dwelling.

An efficiency kitchen is a cooking facility with appliances, a food preparation counter, and storage cabinets that are of reasonable size in relation to the size of the JADU.

Your local agency cannot be more restrictive than this definition. Thus, requirements such as counter or cabinet sizes, specified electrical or gas connections, or appliance types are not authorized by State JADU Law.

Yes. The owner must reside in either the remaining portion of the primary residence or in the newly created JADU. Owner-occupancy is not required when the owner is another governmental agency, land trust, or housing organization.

Yes. Local agencies may prohibit the sale of the JADU separate from the sale of the single-family residence.

You may consult with your local agency or our in-house ADU Expert at (408) 413-3373.

In the meantime, you may also read this ADU Handbook by the California Department of Housing and Community Development.