Hawaii Revised Statutes Division 1. Government § 342D-70

(a) The department may authorize any county to implement a gray water recycling program within its jurisdiction. The gray water recycling program shall be limited to the use of gray water for the purpose of irrigating lawns and gardens. All use of gray water shall conform to the state plumbing code, chapter 3-183, Hawaii administrative rules.

(b) The county seeking authorization shall submit to the department for its approval prior to implementation a detailed gray water recycling plan, including rules and procedures for the proposed program. The plan shall address the appropriateness of the program for the geographic area, the environmental impact of the program on the geographic area, the cost of the program, and any other factors deemed relevant by the department. The department may revoke the authorization at any time.

The department and the counties are encouraged to promote widespread use of gray water consistent with subsection (a) in the interests of water conservation. Any guidelines for the use of gray water for irrigation purposes shall be liberally construed so as to allow widespread use of gray water.

(c) For the purposes of this section, “gray water” shall have the same meaning as in section 342D-1.