Cal. Food & Agr. Code § 62706
The pooling plan shall prescribe the pooling area to be covered by each pool. Any such pooling area shall mean and include a large sales and consuming center together with all intermediate and secondary cities, towns and rural areas, which depend upon and receive their fluid milk supplies from a common producing and supply area, and including the fluid milk producers who produce fluid milk for such sales and consuming area, and including the fluid milk processing plants which receive, process or distribute the fluid milk supplies for such an area.
In establishing pool areas the director shall take into consideration the fact that some producers and processors may produce, or process and distribute, respectively, fluid milk for more than one pool area and therefore may qualify for inclusion and participation in more than one pool. Producers who so qualify for participation in more than one pool shall be permitted to do so on the basis of the proportions of their shipments of fluid milk to each pool area.
Ca. Food and Agric. Code § 62706