Ariz. Rev. Stat. § 45-566
A. For the third management period, 2000 to 2010, the director shall promulgate a management plan for each initial active management area not later than January 1, 1998. The director:
1. Except as provided in section 45-411.01, subsection A and section 45-563.02, subsection B, shall establish in each plan a new irrigation water duty for each farm unit to be reached by the end of the third management period and may establish one or more intermediate water duties to be reached at specified intervals during the third management period. Except as provided in subsection D of this section, the irrigation water duty or intermediate water duties for the third management period shall be calculated as the quantity of water reasonably required to irrigate the crops historically grown in the farm unit and shall be computed by dividing the total irrigation requirement per acre of those crops by an irrigation efficiency of eighty per cent, except that a lower irrigation efficiency may be used for a farm unit or portion of a farm unit determined by the director to have limiting soils or excessive slopes and for a farm unit where orchard crops were historically grown and continue to be grown. After computing the irrigation water duty or intermediate water duties for the third management period, the director may adjust the highest twenty-five per cent of the water duties within an area of similar farming conditions by reducing each water duty in an amount up to ten per cent, except that in making the adjustment, no water duty may be reduced to an amount less than the greater of the following:
13. Shall include in the plans for the Tucson, Phoenix and Pinal active management areas recommendations to the Arizona water banking authority regarding all of the following:
D. A person who is entitled to use groundwater pursuant to an irrigation grandfathered right may apply to the director at any time during the management period for an exemption from the irrigation water duties established pursuant to subsection A, paragraph 1 of this section. The director shall grant the exemption if the person demonstrates to the director's satisfaction that granting the exemption is consistent with achieving the management goal of the active management area and that one of the following applies: