An Attached Accessory Dwelling Unit (ADU) is a housing unit that is added to an existing single-family home and shares a wall with the main dwelling. Similar to a detached ADU, it is designed to be a completely independent unit with its own entrance, kitchen, bathroom, and living area.
Attached ADUs have become increasingly popular in Los Angeles and throughout California due to changes in state laws aimed at addressing the housing shortage.
Here are the typical regulations for building an attached ADU in Los Angeles, although you should check with local planning officials or a planning professional for the most recent regulations:
- Zoning: The property must be zoned for residential use. Some specific types of zones may have different rules.
- Lot Size: There's generally no minimum lot size for ADUs, but the unit must meet other requirements such as setbacks.
- Setbacks: Setbacks are distances a structure must be from property lines. While ADUs often require a 4-foot setback from side and rear property lines, for attached ADUs, the addition usually needs to comply with the existing setback requirements for the primary dwelling.
- Size: The maximum size for an attached ADU is typically up to 1,200 square feet or 50% of the existing primary dwelling, whichever is smaller. However, specific sizes can vary based on local rules and the specifics of the lot and existing dwelling.
- Height: Height restrictions for attached ADUs generally conform to those of the main dwelling. This can depend on the specific zoning of the property.
- Parking: No additional parking is required for the ADU if it is within a half-mile of public transit. Otherwise, one parking space may be required, which could be provided as tandem parking on an existing driveway, in setback areas, or other areas that would not reduce the front yard.
- Owner Occupency: There is no owner-occupancy requirement, meaning the owner is not required to live in either the ADU or the primary dwelling.
- Utilities: The ADU must have necessary utilities, which can either be shared with the main house or separate, depending on local regulations and the preferences of the owner.
- Building Code Compliance: The design and construction of the ADU must comply with all local and state building codes.
Again, these requirements can vary depending on specific situations and locations, so it's crucial to consult with local planning officials or a planning professional for the most accurate information.