(a) For the initial source reduction and recycling element of a countywide integrated waste management plan which is required to be submitted to the board pursuant to Section 41791, the county waste characterization component shall identify the constituent materials which comprise the solid waste generated within the unincorporated area of the county. The information shall be representative of the solid waste generated and disposed of within that area and shall reflect seasonal variations. The constituent materials shall be identified by volume, percentage in weight or its volumetric equivalent, material type, and source of generation which includes residential, commercial, industrial, governmental, or other sources. Future revisions of waste characterization studies shall identify the constituent materials which comprise the solid waste disposed of at permitted disposal facilities.
(b) In adopting or revising regulations implementing subdivision (a), the board shall do all of the following:
(1) Permit the use of studies or data developed on a regional basis and adapted to the conditions which exist in a county preparing its waste characterization component.
(2) Permit the use of preexisting data or studies, including those data and studies prepared by local governments with similar waste characteristics.
(3) Require only that amount of seasonal sampling, and waste characterization only of those categories of waste, necessary to achieve the diversion requirements of paragraph (1) of subdivision (a) of Section 41780.