Cal. WIC § 16548.5

Notwithstanding Chapter 3.5 (commencing with Section 11340) of Part 1 of Division 3 of Title 2 of the Government Code, the department may implement, interpret, or make specific this chapter, in whole or in part, by means of all-county letters or similar written instructions, without taking any further regulatory action. These all-county letters or similar written instructions shall have the same force and effect as regulations.