Top Questions

The following is a summary of frequently asked questions about ADUs. Click here to verify which city or unincorporated community you live in, and then check with your local planning and/or building department for details about how the new state laws are applied where you live

1.      I have a vacant property or a property with a commercial use. Can I build an ADU?

ADUs are accessory to proposed or existing homes. You can apply to build an ADU at the same time or after a home is constructed on your property, but you cannot build an ADU as a stand-alone project on a vacant lot or as part of a commercial building.

2.      Can I rent my ADU?

Yes, but local governments may prohibit the use of an ADU for a short-term rental (see below).

3.      Can I use my ADU for short-term rentals?

Local governments may prohibit the use of an ADU for a short-term rental (for example, less than 30 days) or place requirements on short-term rentals such as registration, taxes and/or limits on the number of days per year that an ADU can be used as a short-term rental. Check with your local planning agency to determine any such restrictions that may apply.

4.      Can I convert my garage to an ADU?

Yes, some garages can be converted. Note that converting a structure not originally built as housing, such as a garage, will trigger requirements to comply with residential building codes (such as windows, doors and insulation). Also, you should ensure that your structure is not overly close to power lines

before construction. Your local power authority can support inquiry. 

6.      Can I use a prefabricated structure as an ADU?

Yes, as long as it is certified to have been constructed under federal standards after June 15, 1976, or certified by the State of California as factory-built housing. As with standard construction, the structure must go through the permit approval process for zoning and/or foundation work as applicable. Consult with your local building department for more information.

7.      Can I use a recreational vehicle or tiny house on wheels as an ADU?

RVs and homes on wheels are regulated as vehicles, not permanent dwelling units, in accordance with State codes. However, some local governments may permit their use as an ADU. Please consult with your local building department for more information.

8.      Will building an ADU increase my property taxes?

Construction of a new ADU will not trigger a reassessment of the entire property. As with other types of new construction, only the value of the new ADU (new construction added) will be added to the property’s assessed value. In the case of legalization of an existing unpermitted ADU, the assessment will depend on whether the ADU’s value was reflected in the last sale price Assessor valuation. If so, the legalization will not result in a reassessment of the ADU, as long as the conversion does not result in additional square footage, or is part of a larger remodeling of the entire residence. For more information, please visit the Los Angeles County Assessor Frequently Asked Questions page on “New Construction.”

10.   What’s the difference between an ADU and a guesthouse?

An ADU is an attached or a detached residential dwelling unit that provides complete independent living facilities for one or more persons and must include a kitchen. Local governments may have different requirements for ADUs and guesthouses. For example, in unincorporated Los Angeles County, a “guesthouse” is detached from the primary residence, does not include a kitchen, and is not rented.

11.   How many ADUs have been built in my city?

Local governments are required to report on the number of ADUs permitted and built-in their Housing Element Annual Progress Reports. You can request a copy of the report from your local planning agency.