California Code, Government Code - GOV § 66654

Within the area of the commission's jurisdiction under subdivisions (b), (c) and (d) of Section 66610, any uses which are in existence on the effective date of this section may be continued, provided, that no substantial change shall be made in such uses except in accordance with this title.

Any owner of property devoted to an existing use or uses may file an application with the commission to determine the nature of such existing use or uses, the extent of territory then devoted to such use or uses, and such additional territory adjacent thereto as may be expected to be reasonably necessary for the expansion of such use or uses during a period of not to exceed 15 years from the date of filing such application.  Not later than 90 days after such filing, the commission after public hearing shall adopt a resolution making such determination.  After the adoption of such resolution no permit need be obtained from the commission for any of the existing use or uses specified in the resolution or for the expansion thereof within the territory described in said resolution.