Cal. Public Resources Code § 40901

(a) The following shall apply with regard to the preparation, revision, and implementation of source reduction and recycling elements pursuant to this part: (1) To determine solid waste amounts in the base year and in the first locally adopted source reduction and recycling element, cities, counties, and regional agencies shall quantify all solid waste generated. For the purposes of this requirement, solid waste generated is equal to existing disposal plus existing diversion, unless modification to these amounts is required pursuant to Section 41801.5. (2) To determine solid waste amounts in subsequent elements, and for the purposes of determining whether the diversion requirements of Section 41780 have been met, cities, counties, and regional agencies shall report the amounts of solid waste disposed of at permitted disposal facilities. For these purposes, cities, counties, and regional agencies are not required to quantify the amounts of solid waste which have been diverted from disposal through recycling or composting, except for diversion which results from recycling and composting programs which are operated or funded by cities, counties, or regional agencies. (3) For revisions of the documents specified in Sections 41032, 41033, 41050, 41070, 41072, 41200, 41260, 41350, 41352, 41370, 41372, 41400, 41402, and 41460, cities, counties, and regional agencies shall follow the procedures identified in paragraph (2). (b) Cities and counties which choose to form a regional agency shall not be required to revise source reduction and recycling elements which were complete at the time of the formation of the regional agency. Any revisions which are needed to reflect program and other changes caused by the formation of a regional agency shall be reflected in the revised source reduction and recycling element submitted by the regional agency at the time of the five-year revision.