Cal. Food and Agricultural Code § 6252

(a) After the district has been formed, an owner of winegrape acreage in the district may present to the board a request in writing for the exclusion of that land or any part of the land from the district upon a showing that the land or part of the land will not be benefited by the activities of the district. Factors that the board may consider in its determination for exclusion shall include an affidavit from the owner that the land has already been affected by phylloxera or other winegrape plant pests and the winegrape plants have been removed from the land, more than 66 percent of the subject parcel is planted with non-vinifera-crossed rootstock, including, but not limited to, St. George, S04, 5C or 5BB rootstock, or that the subject parcel does not have a pest or disease problem that can be controlled by the district. (b) After receipt of the request, the board shall cause an investigation of the parcel of land to be made and, if the board determines that the land or part of the land will not be benefited by the activities of the district, the board shall exclude the winegrape acreage from the district and immediately certify this fact to the county assessor and the county auditor or tax collector. (c) Any owner of winegrape acreage outside of, or otherwise not included in, the district may present to the board a request in writing for inclusion of the land in the district.