California Code, Health and Safety Code - HSC § 17921.8

(a)(1) The department shall review current building standards, conduct research, and develop recommendations regarding building standards for the installation of rainwater catchment systems for nonpotable uses in newly constructed residential dwellings and may propose related building standards to the California Building Standards Commission for consideration during the next regularly scheduled triennial code adoption cycle that commences on or after January 1, 2027. In conducting the research, the department shall actively consult with the State Water Resources Control Board, the Department of Water Resources, the State Department of Public Health, local water agencies and districts, and other interested parties, including, but not limited to, public water system representatives, product manufacturers, local building officials, California-licensed contractors, the building industry, and interested members of the public.

(2) In researching, developing, and proposing voluntary or mandatory building standards under this section, the department may expend funds from the Building Standards Administration Special Revolving Fund, upon appropriation pursuant to Section 18931.7.

(3) Research conducted to propose building standards under this section shall include, but not be limited to, all of the following:

(b)(1) On or before January 1, 2027, the department shall provide a report to the Assembly Committee on Housing and Community Development and the Senate Housing Committee regarding the outcomes of its research and the recommendations developed pursuant to subdivision (a).

(2) A report submitted pursuant to this subdivision shall be submitted in compliance with Section 9795 of the Government Code.

(3) The reporting requirement pursuant to this subdivision is inoperative on January 1, 2029, pursuant to Section 10231.5 of the Government Code.