California Code, Public Resources Code - PRC § 41721

(a) The countywide siting element shall be approved by the county and by a majority of the cities within the county that contain a majority of the population of the incorporated area of the county except in those counties that have only two cities, in which case the element is subject to approval of the city that contains the majority of the population of the incorporated area of the county.  Each city shall act upon the countywide siting element within 90 days after receipt of the siting element.  If a city fails to act upon the siting element within 90 days after receiving the siting element, the city shall be deemed to have approved the siting element as submitted.

(b) Notwithstanding subdivision (a), a siting element providing for an EMSW conversion facility is only required to be approved by the city in which it is located, or if the EMSW is not located in a city, by the county.