California Code, Public Resources Code - PRC § 41710

(a) A county may tentatively reserve an area or areas for the location of a new solid waste transformation or disposal facility or the expansion of an existing transformation or disposal facility even though that reservation of the area or areas is not consistent with the applicable city or county general plan. A reserved area in a countywide siting element is tentative until it is made consistent with the applicable city or county general plan.

(b) If a county has tentatively identified a site expansion or a potential site for a new solid waste transformation or disposal facility in its countywide siting element, that tentative site identification may be deemed a tentative area for the purposes of Sections 41711 and 41712.