(1)(a) By July 1, 2022, the department of health, in consultation with the Washington state building code council and the Washington state association of plumbers and pipefitters who participate in the development of the Uniform Plumbing Code under chapter 19.27 RCW, shall adopt rules for:

(i) Risk-based water quality standards for the on-site treatment and reuse of nonpotable alternative water sources for nonpotable end uses in multifamily residential, commercial, and mixed-use buildings, and district-scale projects, including a mix of multifamily residential, commercial, and mixed-use buildings; and

(ii) Construction standards to adopt the risk-based framework water quality standards.

(b) The department of health must ensure that rules adopted under this subsection take effect by December 31, 2022.

(2) At a minimum, the rules required under subsection (1) of this section must address the following:

(a) Risk-based log reduction targets for the removal of pathogens, such as enteric viruses, parasitic protozoa, and enteric bacteria for alternative water sources, including wastewater from all domestic fixtures, gray water, rainwater, and stormwater for nonpotable end uses such as toilet and urinal supply water, clothes washing, irrigation, and dust suppression;

(b) Treatment and performance requirements;

(c) Water quality monitoring requirements;

(d) Reporting requirements for the treatment, performance, and water quality monitoring results;

(e) Notification and public information requirements;

(f) Cross-connection controls;

(g) Permitting;

(h) Any conflicts the rules adopted in this section have with the department of ecology's municipal stormwater general permit and guidance manuals on stormwater for eastern and western Washington. Any calculations of the amount of water that a property owner or permit holder must make to address runoff from impervious surfaces must reduce the amount of rainwater considered to be stormwater when it is captured to be used for alternative nonpotable end uses in buildings and projects; and

(i) The need for a water right impairment review through the department of ecology.

(3)(a) An on-site treated nonpotable water system in operation before January 1, 2022, must comply with the rules established pursuant to subsection (1) of this section by January 1, 2024.

(b) If a permitting local jurisdiction finds that the permittee is unable to come into compliance with the rules adopted under subsection (1) of this section because the engineering, repair, or replacement of the system is cost-prohibitive, the local jurisdiction may grant the permittee a waiver of compliance with the rules.

(4) The department of health may consult or contract with other public or private entities including, but not limited to, the state building code council and the department of ecology for advice on state building code language, water rights, water quality, and other technical matters relating to adoption of the risk-based water quality standards pursuant to subsection (1) of this section.

(5) For the purposes of this section, "local jurisdiction" includes a county, city, or town.