A. A city, town or county may not limit the use of gray water by rule or ordinance unless, in an initial active management area that has a groundwater management goal of safe yield and that does not contain a part of the central Arizona project aqueduct, effluent has been included in an assured water supply determination pursuant to section 45-576 and the use of gray water would reduce the volume of effluent available to satisfy assured water supply requirements applicable to that determination.

B. For residential gray water treatment systems that are used indoors for toilet flushing, the director may establish by rule minimum requirements that are necessary specifically to address public health or safety concerns.

C. Until rules are adopted pursuant to subsection B of this section, residential gray water may be used indoors for toilet flushing with a gray water treatment system that complies with all of the following:

1. Uses less than four hundred gallons of gray water per day.

2. Is certified to meet standard 350 for residential gray water recycling that is issued by a national sanitary foundation and an American national standards institute.

3. Reasonably precludes human contact with gray water.

4. Provides a dedicated piping system that supplies only treated gray water to the toilet flushing facilities.

5. Provides gray water for toilet flushing only if the system is properly functioning.

D. Any residential gray water treatment system that is installed after the effective date of rules adopted pursuant to subsection B of this section and that includes the use of gray water for indoor toilet flushing shall meet the minimum requirements that are established by those rules.