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An accessory dwelling unit (ADU) also known as a “granny flat”, “in-law unit”, or “secondary dwelling unit”, is a permanent second unit with a full kitchen and bathroom on the same lot as the principal dwelling. ADUs may be attached or detached from the principal dwelling. ADUs may involve new construction, conversion of an existing structure, or designation of an existing home as an accessory dwelling unit so that a new principal structure can be built.

In September 2016, Governor Brown signed two legislative acts that comprised the new law governing ADUs, AB 2299 and SB 1069, both of which came into effect on January 1, 2017. In October 2017, two additional legislative acts, AB 494 and SB 229, were signed into law and came into effect on January 1, 2018. The new statutes amended various sections of Government Code section 65852.2 which regulates accessory dwelling units (formerly called second dwelling units). The County of Ventura adopted an Interim Urgency Ordinance in March 2017 to implement the new state law while a permanent ADU Ordinance was prepared.

Timeline of ADU Ordinance Update:

  • March 14, 2017, the Board of Supervisors adopted an Interim Ordinance (Ordinance No. 4507) to regulate ADUs in non-coastal areas as an Urgency Measure, pursuant to Government Code section 65858.

  • April 18, 2017, the Board of Supervisors adopted an extension to the ADU Interim Ordinance (Ordinance No. 4509). The ADU Interim Ordinance Extension carried over the same provisions that were adopted in Ordinance 4507.

  • September 19, 2017, the Board of Supervisors provided direction to Planning Division staff regarding preparing permanent ADU regulations for both the non-coastal and coastal zones.

  • November 2017 to January 2018, Planning Division staff presented a summary of the proposed ADU ordinance amendments at six different Municipal Advisory Councils and Neighbourhood Councils.

  • January 18, 2018, the Planning Commission voted 4-1 to recommend approval of the proposed amendments to the Non-Coastal and Coastal Zoning Ordinances.

  • February 27, 2018, the Board of Supervisors adopted the amendments to the Non-Coastal and Coastal Zoning Ordinances (Ordinance Nos. 4519 and 4520) as recommended by the Planning Commission.

  • March 29, 2018, Ordinance 4519, which regulates ADUs in the non-coastal areas, goes into effect.

  • Ordinance 4520, which regulates ADUs in coastal areas, is pending approval from the California Coastal Commission. In the Interim, existing Coastal Zoning Ordinance ADU standards remain in effect.

Important Documents regarding Accessory Dwelling Units:

Any questions or comments regarding the Interim ADU Ordinance or the Permanent ADU Ordinance Update can be directed to the project planner, Jennifer Butler, by email at This email address is being protected from spambots. You need JavaScript enabled to view it., or to the assistant planner, Owen Deutsch, at This email address is being protected from spambots. You need JavaScript enabled to view it.