California Code, Health and Safety Code - HSC § 116410

(a) Each public water system with at least 10,000 service connections and with a natural level of fluorides that is less than the minimum established in the regulations adopted pursuant to this section shall be fluoridated in order to promote the public health of Californians of all ages through the protection and maintenance of dental health, a paramount issue of statewide concern. The department shall adopt regulations pursuant to Chapter 3.5 (commencing with Section 11340) of Division 3 of Title 2 of the Government Code, requiring the fluoridation of public water systems. By July 1, 1996, and at 10-year intervals thereafter, each public water system with at least 10,000 service connections shall provide to the department an estimate of the total capital costs to install fluoridation treatment. The regulations adopted by the department shall take effect on January 1, 1997.Capital costs estimates are no longer required after installation of the fluoridation treatment equipment.

(b) The regulations shall include, but not be limited to, the following:

(c) The purpose of the schedule established pursuant to paragraph (4) of subdivision (b) is not to mandate the order in which public water systems receiving funding from private sources must fluoridate their water. Available funds may be offered to any system on the schedule.

(d) The estimates provided to the department pursuant to subdivision (a) of this section and subdivision (g) of Section 116415 of the total capital and associated costs and noncapital operation and maintenance costs related to fluoridation treatments and the similar estimates provided to those sources offering to provide the funds set forth in paragraph (1) of subdivision (a) of Section 116415 shall be reasonable, as determined by the department. A registered civil engineer recognized or employed by the department who is familiar with the design, construction, operation, and maintenance of fluoridations systems shall determine for the department whether the costs are reasonable.

(e) As used in this section and Section 116415, “costs” means only those costs that require an actual expenditure of funds or resources, and do not include costs that are intangible or speculative, including, but not limited to, opportunity or indemnification costs.

(f) Any public water system with multiple water sources, when funding is not received to fluoridate all sources, is exempt from maintaining otherwise required fluoridations levels in areas receiving any nonfluoridated water. The exemption shall be in effect only until the public water system receives funding to fluoridate the entire water system and the treatment facilities are installed and operational.