Cal. WAT § 375

(a) Notwithstanding any other law, any public entity that supplies water at retail or wholesale for the benefit of persons within the service area or area of jurisdiction of the public entity may, by ordinance or resolution adopted by a majority of the members of the governing body after holding a public hearing upon notice and making appropriate findings of necessity for the adoption of a water conservation program, adopt and enforce a water conservation program to reduce the quantity of water used by those persons for the purpose of conserving the water supplies of the public entity.

(b) With regard to water delivered for other than agricultural uses, the ordinance or resolution may specifically require the installation of water-saving devices that are designed to reduce water consumption. The ordinance or resolution may also encourage water conservation through rate structure design.

(c) For the purposes of this chapter, “public entity” means a city, whether general law or chartered, county, city and county, special district, agency, authority, any other municipal public corporation or district, or any other political subdivision of the state.

(d) For the purposes of this section and subdivisions (b) and (c) of Section 377, “person” means any person, firm, association, organization, partnership, business, trust, corporation, company, or public agency, including any city, county, city and county, district, joint powers authority, or any agency or department of a public agency.