Attached ADUs Size Limit If you're going to build an attached ADU in a primary residence or new ADU, its square footage can't exceed 50% of the home's square footage. Additionally, the attached ADU size in Los Angeles city limits also involves that it can't exceed the house's height.
CalHFA's ADU Grant Program has already created more housing units in California by providing grants up to $40,000 to reimburse pre-development and non-recurring closing costs associated with the construction of an ADU.
ADUs must be equipped with permanent facilities for independent living, but JADUs need only have an “efficiency” kitchen and may share some facilities with the primary dwelling. The maximum size allowed for a JADU is 500 sq. ft., while two-bedroom ADUs in San Jose may be up to 1,000 sq. ft.
An attached ADU may be up to fifty percent of the existing living area of the primary residence. A detached ADU is limited to a maximum total floor area of 1,200 square feet. For more information on ADUs, please visit our ADU building page.
Can I rent my ADU in San Jose? Yes, many homeowners we've worked with in San Jose rent out their ADUs, given the high demand for housing and high rents. Short-term rentals of less than 30 days are not allowed in San Jose, but you can rent out your ADU on platforms like Airbnb for 30+ days.