Cal. Water Code § 13553

(a) The Legislature hereby finds and declares that the use of potable domestic water for toilet and urinal flushing in structures is a waste or an unreasonable use of water within the meaning of Section 2 of Article X of the California Constitution if recycled water, for these uses, is available to the user and meets the requirements set forth in Section 13550, as determined by the state board after notice and a hearing.
(b) The state board may require a public agency or person subject to this section to furnish any information that may be relevant to making the determination required in subdivision (a).
(c) For purposes of this section and Section 13554, “structure” or “structures” means commercial, retail, and office buildings, theaters, auditoriums, condominium projects, schools, hotels, apartments, barracks, dormitories, jails, prisons, food handling and processing facilities, reformatories, and other structures as determined by the state board.
(d) Recycled water may be used in condominium projects, as defined in Section 4125 or 6542 of the Civil Code, subject to all of the following conditions:
1. (1) Prior to the indoor use of recycled water in any condominium project, the agency delivering the recycled water to the condominium project shall file a report with, and receive written approval of the report from, the state board. The report shall be consistent with the provisions of Title 22 of the California Code of Regulations generally applicable to dual-plumbed structures and shall include all the following:
  1. (A) That potable water service to each condominium project will be provided with a backflow protection device approved by the state board to protect the agency’s public water system, as defined in Section 116275 of the Health and Safety Code. The backflow protection device approved by the state board shall be inspected and tested annually by a person certified in the inspection of backflow prevention devices.
  2. (B) That any plumbing modifications in the condominium unit or any physical alteration of the structure will be done in compliance with state and local plumbing codes.
  3. (C) That each condominium project will be tested by the recycled water agency or the responsible local agency at least once every four years to ensure that there are no indications of a possible cross connection between the condominium’s potable and nonpotable systems.
  4. (D) That recycled water lines will be color coded consistent with current statutes and regulations.
2. (2) The recycled water agency or the responsible local agency shall maintain records of all tests and annual inspections conducted.
3. (3) The condominium’s declaration, as defined in Section 4135 or 6546 of the Civil Code, shall provide that the laws and regulations governing recycled water apply, shall not permit any exceptions to those laws and regulations, shall incorporate the report described in paragraph (1), and shall contain the following statement:
  “NOTICE OF USE OF RECYCLED WATER
  This property is approved by the State Water Resources Control Board for the use of recycled water for toilet and urinal flushing. This water is not potable, is not suitable for indoor purposes other than toilet and urinal flushing purposes, and requires dual plumbing. Alterations and modifications to the plumbing system require a permit and are prohibited without first consulting with the appropriate local building code enforcement agency and your property management company or owners’ association to ensure that the recycled water is not mixed with the drinking water.”
(e) The state board may adopt regulations as necessary to assist in the implementation of this section.
(f) This section shall only apply to condominium projects that are created, within the meaning of Section 4030 or 6580 of the Civil Code, on or after January 1, 2008.
(g) This section and Section 13554 do not apply to a pilot program adopted pursuant to Section 13553.1.