Cal. Bus. & Prof. Code § 13350

(a) The board of supervisors of any county or city and county that has adopted or that adopts an ordinance for the purposes of determining the pricing accuracy of a retail establishment using a point-of-sale (POS) system, shall base the initial standard inspection of the POS system on the following criteria:
1. (1) The initial standard inspection shall be performed by collecting a random sample of items that shall include a maximum of 50 percent sale items from either:
  1. (i) One department of a retail store.
  2. (ii) Multiple areas of a retail store.
  3. (iii) The entire store.
2. (2) The initial standard inspection shall be performed by testing a minimum random sample of 10 items for a retail establishment with three or fewer POS checkout registers.
3. (3) The initial standard inspection shall be performed by testing a minimum random sample of 25 items for a retail establishment with 4 to 9 POS checkout registers.
4. (4) The initial standard inspection shall be performed by testing a minimum random sample of 50 items for retail establishments with 10 or more POS checkout registers.
5. (5) The sealer shall verify that the lowest advertised, posted, marked, displayed, or quoted price is the same as the price displayed or computed by the point-of-sale equipment or printed receipt. Only items computed at a higher price than the lowest advertised, posted, marked, displayed, or quoted price shall be considered not in compliance.
6. (6) The minimum random sample size shall not apply to inspections of any establishment at which fewer items than the number specified as the minimum sample size are marked or displayed with a posted or advertised item price.
7. (7) The maximum percentage of sale item restriction in paragraph (1) shall not apply to inspections of any establishment at which a marketing or promotional practice does not enable the sampling of the minimum required percentage of nonsale items, such as “Everything In Store 50 percent Off” or the like.
8. (8) The compliance rate percentage of a retail establishment shall be determined by dividing the number of items in compliance by the sample size multiplied by 100.
(b) Enforcement action may be taken for any item not in compliance.
(c) The sealer may reinspect any retail facility that has a compliance rate of less than 98 percent.
(d) The board of supervisors, by ordinance, may charge a point-of-sale system inspection fee or an annual registration fee, not to exceed the county’s total cost of inspecting or testing the accuracy of prices accessed or generated by the system pursuant to this section.
(e) The board of supervisors, by ordinance, may charge a reinspection fee for reinspections of a retail establishment that fails the prior inspection, not to exceed the county’s total cost of reinspecting or testing the accuracy of prices accessed or generated by the system pursuant to this section.