A. The Board shall adopt regulations regarding the use of gray water and rainwater. The regulations shall (i) describe the conditions under which gray water and rainwater may appropriately be used and for what purposes; (ii) include categories of gray water, such as types of used household water and used water from businesses, that are appropriate for reuse; and (iii) include a definition of gray water that excludes used toilet water. The regulations shall also provide standards for the use of rainwater harvesting systems, including systems that collect rainwater for use by commercial enterprises but do not provide water for human consumption, as defined in § 32.1-167. Such regulations shall not apply to water not for human consumption, as defined in § 32.1-167, including gray water and rainwater, that is produced and utilized by any facility that is permitted through a Virginia Pollutant Discharge Elimination System permit or General Virginia Pollution Abatement permit.