California Code, Health and Safety Code - HSC § 18940.7

(a) For purposes of this section, “water reuse system” includes both of the following:

(b) The commission shall, commencing with the next triennial edition of the California Building Standards Code (Title 24 of the California Code of Regulations), research, develop, and propose building standards, including voluntary Tier 1 or Tier 2 standards of the California Green Building Standards Code (Part 11 of Title 24 of the California Code of Regulations), to reduce potable water use in new nonresidential buildings, including consideration of requiring installation of water reuse systems and consideration of requiring preplumbing of buildings to allow future use of recycled water, onsite treated graywater, or other alternative water sources. In developing these standards, the commission may limit or exempt the application of standards based on occupancy, building type, building size, development size, availability or planned availability of recycled water, or as otherwise determined appropriate.

(c) The commission shall perform a review of water efficiency and water reuse standards in the California Buildings Standards Code every three years thereafter and update as needed.

(d) In developing and proposing building standards under this section, the commission is authorized to expend funds from the Building Standards Administration Special Revolving Fund, upon appropriation pursuant to Section 18931.7.