Az Water Co v. Az Dept of Water Resources ( 2004 )


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  •                    SUPREME COURT OF ARIZONA
    En Banc
    ARIZONA WATER COMPANY, an         )   Arizona Supreme Court
    Arizona corporation,              )   No. CV-03-0321-PR
    )
    Plaintiff-Appellee )    Court of Appeals
    Cross-Appellant, )   Division One
    )   No. 1 CA-CV 02-0276
    v.               )
    )
    ARIZONA DEPARTMENT OF WATER       )   Maricopa County
    RESOURCES, H.R. GUENTHER, in his )    Superior Court
    capacity as Director of the       )   Nos. CV 90-001840
    Arizona Department of Water       )        CV 99-008015
    Resources,                        )
    )
    Defendants-Appellants )
    Cross-Appellees, )    O P I N I O N
    )
    ARIZONA CORPORATION COMMISSION,   )
    )
    Intervenor-Appellee. )
    )
    __________________________________)
    Appeal from the Superior Court in Maricopa County
    The Honorable Roger W. Kaufman, Judge
    VACATED AND REMANDED
    Opinion of the Court of Appeals, Division One
    
    205 Ariz. 532
    , 
    73 P.3d 1267
    AFFIRMED IN PART, VACATED IN PART
    ARIZONA DEPARTMENT OF WATER RESOURCES                         Phoenix
    By: W. Patrick Schiffer
    Kenneth C. Slowinski
    Nicole D. Swindle
    Attorneys for Defendants-Appellants/Cross-Appellees
    Arizona Department of Water Resources
    FENNEMORE CRAIG                                                               Phoenix
    By: Timothy Berg
    Norman D. James
    Thomas R. Wilmoth
    Attorneys for Plaintiff-Appellee/Cross-Appellant
    Arizona Water Company
    SALMON LEWIS & WELDON PLC                                 Phoenix
    By: M. Byron Lewis
    Lisa M. McKnight
    Attorneys for Amici Curiae
    Salt River Valley Water Users’ Association and
    Salt River Project Agricultural Improvement and Power District
    H U R W I T Z, Justice
    ¶1           The   issue   in      this    case   is    whether    the    1990-2000
    management    plan   adopted       by     the   Arizona    Department     of    Water
    Resources (“ADWR” or the “Department”) for the Phoenix active
    management    area   violated        the    Arizona     Groundwater      Code    (the
    “Code”).     We conclude that ADWR was statutorily authorized to
    promulgate those portions of the management plan in which per
    capita conservation requirements were directly imposed on water
    providers,     but   was     not     mandated      by     the   Code     to     impose
    conservation requirements directly on all “end users.”                        We also
    conclude ADWR may consider a provider’s use of Central Arizona
    Project    (“CAP”)   water      in      calculating     that    provider’s      total
    annual per capita water use.
    2
    I.
    A.
    ¶2            The Groundwater Code, Ariz. Rev. Stat. (“A.R.S.”) §§
    45-401 to -704 (2003 & Supp. 2003), was originally enacted as
    part of the Groundwater Management Act of 1980, 1980 Ariz. Sess.
    Laws,   4th    Spec.    Sess.,    ch.    1.     In    adopting     the    Code,   the
    legislature found “that the people of Arizona are dependent in
    whole or in part upon groundwater basins for their water supply
    and that in many basins and sub-basins withdrawal of groundwater
    is greatly in excess of the safe annual yield.”                      A.R.S. § 45-
    401(A).       The legislature further found that these withdrawals
    were “threatening to destroy the economy of certain areas of
    this state and [were] threatening to do substantial injury to
    the general economy and welfare of this state and its citizens.”
    Id.
    ¶3            The Code was designed to protect the state’s economy
    and welfare, and to “provide a framework for the comprehensive
    management     and     regulation   of    the   withdrawal,        transportation,
    use,    conservation       and    conveyance         of   rights     to    use    the
    groundwater in this state.”             A.R.S. § 45-401(B).        Responsibility
    for these critical matters was placed in the hands of ADWR,
    A.R.S. § 45-102(A) (2003), headed by a Director, A.R.S. § 45-
    102(B),   with       sweeping    “general     control     and    supervision”     of
    groundwater, A.R.S. § 45-103(B) (2003).
    3
    ¶4           The Groundwater Code established four initial “active
    management    areas”    (“AMAs”).          A.R.S.    §   45-411(A).1     ADWR    was
    required to adopt five successive conservation management plans
    for each AMA, one for each decade beginning in 1980.2                      A.R.S. §
    45-563(A).      For the Tucson, Phoenix, and Prescott AMAs, the
    Code’s    “management       goal”    was       to   establish    “safe-yield,”     a
    balance   between     the   amount    of       groundwater   withdrawn     and   the
    amount    naturally     and    artificially         recharged,    A.R.S.    §    45-
    561(12), by no later than 2025.             A.R.S. § 45-562(A).3
    ¶5           The Groundwater Code required, as part of the first
    management plan for the Tucson, Phoenix, and Prescott AMAs, that
    the Director establish “[a] conservation program for all non-
    1
    The four original AMAs were the Tucson, Phoenix,
    Prescott, and Pinal AMAs.   A.R.S. § 45-411(A). In 1994, the
    legislature created the Santa Cruz AMA from a portion of the
    Tucson AMA. A.R.S. § 45-411.03(A).
    2
    The first four management plans apply, respectively,
    to the four decades between 1980 and 2020.    A.R.S. §§ 45-564
    (first plan), -565 (second plan), -566 (third plan), -567
    (fourth plan).   The fifth management plan will apply between
    2020 and 2025. A.R.S. § 45-568.
    3
    For the Pinal AMA, the “management goal” was “to allow
    development of non-irrigation uses as provided in this chapter
    and to preserve existing agricultural economies . . . for as
    long as feasible, consistent with the necessity to preserve
    future water supplies for non-irrigation uses.”     A.R.S. § 45-
    562(B).   For the Santa Cruz AMA, the “management goal” was to
    “maintain a safe-yield condition . . . and to prevent local
    water tables from experiencing long-term declines.”      A.R.S. §
    45-562(C).
    4
    irrigation uses of groundwater.”4                    A.R.S. § 45-564(A)(2).                For
    municipal uses,5 the initial plans were to require “reasonable
    reductions      in   per   capita    use        and     such    other        conservation
    measures as may be appropriate for individual users.”                              Id.     For
    the   second    management    period,          the    Director        was    required      to
    “[e]stablish additional conservation requirements for all non-
    irrigation uses of groundwater.”                 A.R.S. § 45-565(A)(2).                  With
    respect   to    municipal    uses,        the    second        plan    “shall        require
    additional     reasonable    reductions         in     per   capita         use    to    those
    required in the first management period and use of such other
    conservation     measures    as     may    be        appropriate       for        individual
    users.”   Id.
    ¶6           The Department’s primary method of implementing the
    Code’s conservation requirements has been the “Total Gallons Per
    4
    “Non-irrigation use” is defined by the Code, for all
    but the Santa Cruz AMA, as “a use of groundwater other than an
    irrigation use.”   A.R.S. § 45-402(28)(a).  “Irrigation use” is
    defined generally as the use of groundwater to produce plants
    for various agricultural purposes. A.R.S. § 45-402(23)(a).
    5
    “Municipal use” is defined as
    all non-irrigation uses of water supplied by a city,
    town, private water company or irrigation district,
    except for uses of water, other than Colorado river
    water, released for beneficial use from storage,
    diversion or distribution facilities to avoid spilling
    that would otherwise occur due to uncontrolled surface
    water inflows that exceed facility capacity.
    A.R.S. § 45-561(11).
    5
    Capita      Per     Day”    (“GPCD”)    programs   in     the     management       plans.
    These programs limit the total quantity of water a provider may
    deliver to its customers each year.6                 This approach places the
    principal burden of achieving reductions in groundwater use on
    water providers, who are charged in ADWR’s management plans with
    reducing their total GPCD during each management period.                            While
    the second management plan (“SMP”) for the Phoenix AMA directly
    regulates groundwater usage by some high-volume end users, the
    Phoenix SMP does not impose per capita conservation requirements
    directly on all end users.7
    B.
    ¶7                Arizona   Water   Company     (“AWC”)     is    a    private      water
    company      operating       in   the   Phoenix    AMA.          See   A.R.S.      §    45-
    402(30)(a) (defining “[p]rivate water company”).                         Because AWC
    supplies          groundwater     for   non-irrigation          use,    it    is       also
    classified under the Groundwater Code as a municipal provider.
    See A.R.S. § 45-561(10) (defining “[m]unicipal provider”).                              In
    1988,       AWC    filed    administrative      petitions       with   ADWR     seeking
    6
    The total annual quantity of water a provider                                can
    deliver to its customers is obtained by multiplying                                    the
    provider’s GPCD (set by ADWR in the management plan) by                                the
    company’s service area population by the number of days in                             the
    year.
    7
    The end users subject to direct regulation in the
    Phoenix SMP include turf-related facilities (parks, golf courses
    and common areas of housing developments), publicly owned
    rights-of-way, and new large cooling users.
    6
    review   and    rehearing     of     the   Director’s            order      adopting   the
    Phoenix SMP.        The Director denied relief.                      In 1990, AWC filed
    suit in superior court seeking judicial review of the Director’s
    decision.
    ¶8          AWC’s     complaint      alleged      that     the        SMP   violated   the
    Groundwater     Code     because      it       did   not        impose        conservation
    regulations directly on AWC’s end users.                             The complaint also
    challenged various other provisions in the SMP applicable to
    AWC’s water utility companies.                 Shortly after the complaint was
    filed, AWC applied to ADWR for administrative review of the GPCD
    requirements     imposed      upon    several        of        its    water    utilities,
    including its Apache Junction system.                 The superior court action
    was stayed pending the Director’s review of AWC’s administrative
    applications.        AWC and ADWR eventually resolved all disputes
    except those pertaining to the Apache Junction system.                                 The
    Apache Junction system remained out of compliance with the GPCD
    requirements     of     the    SMP      because           of     rapidly       increasing
    nonresidential uses of water, primarily by golf courses, without
    proportionate increases in the population served by the utility.8
    8
    When the SMP was promulgated in 1989, the Apache
    Junction system pumped 2400 acre feet of groundwater, and served
    a population of 20,557.   In 1997, the population of the system
    had increased by about fifty percent, but the use of groundwater
    had increased sixty-three percent to 3920 acre feet.
    7
    ¶9            After the parties’ failure to resolve the dispute over
    the     Apache      Junction        system,        an     administrative         law        judge
    conducted      a    hearing      and   recommended          a    recalculation         of    the
    Apache    Junction        GPCD    based      on    updated       population      estimates.
    Even     after      the    recalculation,          however,       the   Apache     Junction
    system was still not in compliance with the SMP, and the judge
    recommended denial of AWC’s other requests for relief.                             In 1999,
    the     Director          adopted      the        recommended       decision           of    the
    administrative law judge, with minor modifications.                                AWC then
    filed     suit      in    superior     court        seeking       review    of    the       1999
    decision, and the court consolidated this suit with the pending
    1990 action.
    ¶10           AWC’s superior court complaints alleged that the GPCD
    mandates in the SMP conflicted with requirements imposed by the
    Arizona       Corporation        Commission         under       AWC’s   certificates          of
    necessity      and       convenience      to      serve    customers       in    the    Apache
    Junction      area.        The    superior         court    therefore      requested         the
    Commission to intervene.               The Commission did so and argued that
    ADWR    had    no    authority       to   tell       a    water    utility       subject      to
    Commission       regulation       which      customers      it     could    or    could      not
    serve.        Despite      its    legal      position,       the    Commission         saw    no
    present irreconcilable conflict between it and ADWR with respect
    to AWC’s situation, and suggested that because it had worked
    collaboratively with “sister state agencies” in the past when
    8
    issues    of   overlapping       regulation         were    presented,   it    was
    confident that it would be able to work with ADWR should a
    conflict arise in the future.
    ¶11          In 2002, the superior court entered a judgment holding
    that the SMP was unenforceable “because it fails to address
    water utilization by end users.”9             The court remanded the case to
    ADWR with directions to adopt an amended plan, and forbade the
    Department     from   enforcing    the       GPCD   requirement    for   the   AWC
    Apache    Junction      system     “[u]ntil          such    deficiencies      are
    corrected.”
    C.
    ¶12          ADWR appealed, and in a 2-1 opinion, the court of
    appeals affirmed the superior court judgment insofar as it held
    the SMP invalid for failure to impose conservation requirements
    on end users.     Ariz. Water Co. v. Ariz. Dep’t of Water Res., 
    205 Ariz. 532
    , 
    73 P.3d 1267
     (App. 2003).                The majority acknowledged
    that “there is no specific statutory provision by which the
    legislature definitively ordered the Department to create and
    impose conservation measures for end users.”                  
    Id.
     at 537 ¶ 18,
    9
    At the time of the trial court’s decision in 2002, the
    SMP, which covered the decade from 1990 to 2000, had long since
    expired. The issues raised in this case are not moot, however,
    because ADWR’s third management plan is virtually identical in
    all relevant respects to the SMP and AWC currently has an action
    pending in superior court challenging that plan.      See Ariz.
    Water Co. v. Ariz. Dep’t of Water Res., 
    205 Ariz. 532
    , 535 ¶ 8
    n.1, 
    73 P.3d 1267
    , 1270 n.1 (App. 2003).
    9
    
    73 P.3d at 1272
    .          Nonetheless, citing various provisions of the
    Groundwater       Code,    the    majority      below    “develop[ed]        a    firm
    conviction that the legislature intended just that.”                        
    Id.
        The
    majority concluded that
    common sense dictates that if one is assigned the duty
    of conserving a limited resource like groundwater, one
    needs   the  authority,   and  one  must   assume  the
    corresponding responsibility, to manage the resource
    throughout its entire cycle, from extraction to
    transportation to consumption and even recharge.   And
    if the manager is to obtain the desired conservation
    result, all those participating in the cycle must be
    managed directly in regard to their conservation
    responsibility, including the customer who uses the
    groundwater and not just the provider who extracts,
    transports, and delivers it to him.
    
    Id.
    ¶13          Judge      Irvine   dissented      from    this    conclusion.        He
    relied primarily on A.R.S. § 45-565(A)(2), which requires the
    SMP   to   include        for    municipal     uses     “additional        reasonable
    reductions in per capita use to those required in the first
    management period and use of such other conservation measures as
    may be appropriate for individual users.”                     
    205 Ariz. at
    547 ¶
    78,   
    73 P.3d at 1282
       (Irvine,      J.,    concurring      in   part   and
    dissenting    in     part).       Judge    Irvine      read    this   language     as
    authorizing the Department to impose conservation requirements
    directly on end users, but not mandating such direct regulation.
    
    Id.
     at 547-48 ¶¶ 76-80, 
    73 P.3d at 1282-83
    .                        He also parted
    company with the majority on its “common sense” view of the
    10
    Code, arguing that it was not obvious that direct regulation of
    all end users was sensible policy, and that in any event the
    legislature        had       left        such    decisions        to     the        Director’s
    discretion.        
    Id.
     at 548 ¶¶ 81-82, 
    73 P.3d at 1283
    .
    ¶14          Although        it     concluded         that     management       plans          must
    regulate     end    users,         the    majority       below       declined       to    decide
    whether    the     Groundwater           Code    gave    ADWR     authority         to    impose
    conservation       requirements           directly      on   providers         even       in   the
    presence of comprehensive regulation of end users, finding that
    AWC had not raised the issue.                   
    Id.
     at 538 ¶ 27, 
    73 P.3d at 1273
    .
    Judge Irvine, however, concluded that AWC had raised this issue,
    and   explained         in   detail       his   view     that     the    legislature           had
    authorized ADWR to impose conservation requirements directly on
    providers.          
    Id.
          at    544-46       ¶¶    60-73,     
    73 P.3d at 1279-81
    (concurring      and      dissenting        opinion).          The    majority       noted      in
    dictum that “if we believed Arizona Water had properly raised
    the   issue,       we    would      respond      to     Arizona       Water’s       contention
    precisely as has our dissenting colleague.”                          
    Id.
     at 538 ¶ 27, 
    73 P.3d at 1273
    .
    ¶15          Finally,        the    court       of    appeals     turned       to    an    issue
    “presented to the superior court but not decided by it”: whether
    ADWR “is authorized to include Central Arizona Project water
    used by a provider in determining that provider’s compliance
    with its total GPCD requirements.”                      
    Id.
     at 536 ¶ 13, 
    73 P.3d at
    11
    1271.    The court unanimously concluded that the Groundwater Code
    authorized ADWR to consider use of CAP water in determining a
    provider’s compliance with the GPCD.                   
    Id.
     at 541-43 ¶¶ 47-52, 
    73 P.3d at 1276-78
    ; 
    id.
     at 543 ¶ 58, 
    73 P.3d at 1278
     (concurring
    and dissenting opinion).
    ¶16         ADWR petitioned this court for review of the opinion
    below insofar as it vacated the SMP for failure sufficiently to
    regulate end users.          AWC cross-petitioned for review on the CAP
    water issue.       We granted review of both petitions because of the
    statewide     importance       of    the     issues       presented.            We     have
    jurisdiction pursuant to Article 6, Section 5(3) of the Arizona
    Constitution, Arizona Rule of Civil Appellate Procedure 23, and
    A.R.S. § 12-120.24 (2003).            Because the case involves issues of
    statutory    interpretation,         our    review      is   de   novo.      Bilke       v.
    State, 
    206 Ariz. 462
    , 464 ¶ 10, 
    80 P.3d 269
    , 271 (2003).
    II.
    ¶17         This case presents three related issues of statutory
    interpretation.             First,    we        must    determine        whether        the
    Groundwater    Code    authorizes      ADWR      to    impose     GPCD    requirements
    directly on municipal providers such as AWC.                         If we conclude
    that ADWR has that statutory authority, we must next decide
    whether the Code requires that the Director, as a prerequisite
    for     imposing     such     GPCD     requirements,          must       also        impose
    conservation requirements directly on all end users.                            Finally,
    12
    if we conclude that ADWR can impose GPCD requirements directly
    on AWC, we must also decide whether the Code permits ADWR to
    consider CAP water use in determining whether AWC has exceeded
    the mandated GPCD.
    A.
    ¶18          AWC first argues that the Code provides no authority
    for   ADWR   to   impose   GPCD   requirements   directly   on   municipal
    providers.10      The argument is grounded on A.R.S. § 45-565(A)(2),
    which provides that the SMP “shall require additional reasonable
    reductions in per capita use to those required in the first
    management period and use of such other conservation measures as
    may be appropriate for individual users.”         See also A.R.S. § 45-
    564(A)(2) (containing parallel language applicable to the first
    management plan).      AWC contends that because the statute refers
    to per capita “use,” it confers upon ADWR no authority to impose
    GPCD requirements on providers, as opposed to end users, of
    groundwater.      Rather, AWC contends, municipal providers may only
    be regulated under A.R.S. § 45-565(A)(5), which requires the
    10
    We agree with Judge Irvine that AWC properly raised
    this issue in the court of appeals. Ariz. Water Co., 
    205 Ariz. at
    544 ¶¶ 60-61, 
    73 P.3d at 1279
     (concurring and dissenting
    opinion).   In any event, because this court can affirm the
    superior court’s judgment on any basis supported by the record,
    AWC may raise this argument here. See Cross v. Cross, 
    94 Ariz. 28
    , 31, 
    381 P.2d 573
    , 575 (1963) (noting that this court “will
    consider any legal theory within the issues and supported by the
    evidence which tends to support and sustain the judgment of the
    trial court”).
    13
    Director      to     impose         “additional         economically             reasonable
    conservation requirements” on private water companies, but does
    not refer expressly to per capita use reductions.
    ¶19          The   premise     of     AWC’s      argument      is   that     a    municipal
    provider does not “use” groundwater.                    However, the language of
    the Code is directly to the contrary.                          Section 45-565.01(A)
    requires     management       plans     to       make     available        to     municipal
    providers an alternative “non-per capita conservation program”
    (“NPCCP”).         Before     the     Director      can       grant    the       provider’s
    application to participate in certain NPCCPs, he must make “a
    preliminary        determination        that        the       municipal          provider’s
    projected     groundwater       use    is     consistent        with       achieving    the
    management goal of the active management area.”                             A.R.S. § 45-
    565.01(E)(3)       (governing       applications        for    programs         established
    under § 45-565.01(C)(5)) (emphasis added); see also A.R.S. § 45-
    565.01(E)(4)       (containing        similar      language         with     respect       to
    applications for programs established under § 45-565.01(C)(6)).
    The    legislature     thus     plainly       contemplated          that     a    municipal
    provider’s transfer of groundwater to end users can itself be a
    “use” of that groundwater.
    ¶20          More significantly, the statute governing NPCCPs makes
    plain that the legislature intended that ADWR have the authority
    under A.R.S. § 45-565(A)(2) to impose GPCD requirements directly
    on    municipal    providers.         Section      45-565.01(H)        states       that   a
    14
    municipal provider who has filed an NPCCP application “shall
    comply with the per capita conservation requirements established
    under § 45-565, subsection A, paragraph 2 until the director
    approves the application.”                   The same statute provides that after
    the application is approved, “the provider is exempt from the
    per capita conservation requirements prescribed under § 45-565,
    subsection        A,        paragraph        2.”             This     language       conclusively
    demonstrates           that       the    legislature             contemplated             that     GPCD
    requirements could be imposed directly on municipal providers.
    It would make no sense otherwise to offer NPCCP programs, which
    are    designed        as        alternatives           to    otherwise       applicable           GPCD
    requirements,          to    municipal        providers.              Indeed,       because       NPCCP
    programs are only available to municipal providers, and not to
    individual        end        users,      §     45-565.01(H)             would        be     entirely
    superfluous       if     municipal         providers           were    not    subject       to    GPCD
    requirements in the first place.
    B.
    ¶21          AWC       next       argues     that       before        ADWR    can    impose        GPCD
    requirements       on        a    municipal        provider,          it     must    also        impose
    conservation requirements directly on the provider’s end users.
    This is the issue that divided the court below.
    ¶22          We start from the premise, candidly acknowledged both
    by    AWC   and    the       majority        below,          “that    there    is    no     specific
    statutory     provision             by     which        the     legislature          definitively
    15
    ordered    the   Department    to    create     and    impose   conservation
    measures for end users.”        Ariz. Water Co., 
    205 Ariz. at
    537 ¶
    18, 
    73 P.3d at 1272
    .       Nonetheless, the court of appeals, based
    on its review of certain provisions of the Code, “develop[ed] a
    firm conviction that the legislature intended just that.”                    
    Id.
    Our reading of the Code leads us to the opposite conclusion.                 We
    hold that while the Code authorizes ADWR to impose conservation
    requirements directly on end users, it does not require that the
    Director   always   do   so,   or   that   he   must   impose   requirements
    directly on all end users.
    ¶23        The first provision of the Code cited by the majority
    below, A.R.S. § 45-492(A)(2), simply provides that “a city, town
    or private water company shall have the right to withdraw and
    transport groundwater,” and the “landowners and residents” may
    use   groundwater    delivered      to     them,   “subject     to   .   .     .
    [c]onservation requirements developed by the director pursuant
    to article 9 of this chapter [A.R.S. §§ 45-561 to -578].”                This
    statute does not mandate that these conservation requirements be
    imposed directly on end users; instead, it merely requires that
    groundwater use in an AMA be subject to whatever conservation
    requirements the Director promulgates under article 9.
    ¶24        AWC also relies on A.R.S. § 45-563(A).               Section 45-
    563(A) generally requires the Director to promulgate management
    plans for each AMA for the five management periods, and provides
    16
    that     “[t]he     plans     shall     include     a     continuing       mandatory
    conservation program for all persons withdrawing, distributing
    or    receiving     groundwater       designed    to     achieve     reductions      in
    withdrawals of groundwater.”              Notably, this statute does not
    require the Director to promulgate separate programs for each of
    these groups.       Instead, it mandates that each plan include such
    a program.        The fact that the onus for complying with the GPCD
    program falls primarily on providers surely does not render it
    anything other than a “mandatory conservation program” under §
    45-563(A).      And, because the GPCD definitively limits the amount
    of groundwater that end users in an AMA may receive, it is also
    surely a “program for all persons . . . receiving groundwater,”
    as contemplated by the statute.
    ¶25           As did the majority below, AWC places primary reliance
    on     the   parallel   provisions       of     A.R.S.    §§     45-564(A)(2)      and
    -565(A)(2), which govern the first and second management plans.
    Section      45-564(A)(2)     requires    that    the    first      plan   contain   a
    conservation       program,    which     with    respect       to   municipal     uses
    “shall require reasonable reductions in per capita use and such
    other conservation measures as may be appropriate for individual
    users.”       Section 45-565(A)(2) provides that for municipal uses
    the second plan “shall require additional reasonable reductions
    in per capita use to those required in the first management
    period and use of such other conservation measures as may be
    17
    appropriate          for    individual        users.”            AWC     argues      that     these
    subsections mandate that the SMP include conservation measures
    imposed directly on individual users.
    ¶26           AWC’s        reading       of   these     provisions           is    flawed.        The
    final clause of each statute requires only that the plan include
    “such   other        conservation         measures         as    may    be    appropriate         for
    individual users.”                This clause does not require the imposition
    of conservation measures on end users.                                 Instead, the statute
    tells   the     Director          to    impose      only     such      measures      “as    may    be
    appropriate,” leaving open the possibility that he may conclude
    that no such measures, or only limited ones, are appropriate.
    Thus,     any    purported             requirement         for    mandatory         conservation
    requirements on all end users must necessarily come from the
    previous clause of each statute, which provides that the program
    developed       by    the     Director        for     municipal        uses       “shall   require
    reasonable reductions in per capita use,” A.R.S. § 45-564(A)(2),
    or “additional reasonable reductions in per capita use to those
    required in the first management period,” A.R.S. § 45-565(A)(2).
    ¶27           However, neither of these provisions states that the
    portion    of    the        plan    requiring         “reasonable        reductions         in    per
    capita use” must be imposed directly on end users.                                   Rather, the
    statutes      each     provide         that   the      “program        shall       require”      such
    reductions.          A.R.S. §§ 45-564(A)(2) (emphasis added), -565(A)(2)
    (same).         The        GPCD    program       in    the       Phoenix      SMP    meets       that
    18
    statutory requirement.                 It requires reductions in per capita
    use,     even    if        the     requirement       is   achieved      through        direct
    regulation of AWC’s spigot, rather than through individualized
    regulation of each user’s faucet.
    ¶28           AWC also suggests that §§ 45-564(A)(2) and -565(A)(2)
    only     pertain          to     regulation     of    end     users,     and        that   the
    requirement          in    each     statute    for    plans    requiring       “reasonable
    reductions in per capita use” must therefore necessarily require
    imposition of such measures on end users.                            But this reading
    effectively rewrites the statutory scheme.                       For example, § 45-
    565(A)(2) provides that for municipal uses, “the program shall
    require additional reasonable reductions in per capita use . . .
    and     use     of        such     other    conservation      measures         as    may   be
    appropriate for individual users.”                    AWC reads the statute as if
    it     instead       provided        that     “the   program     shall     require         for
    individual users additional reductions in per capita use . . .
    and     use     of        such     other    conservation      measures         as    may   be
    appropriate.”             But such a reading would mean that § 45-565(A)(2)
    provided no basis for imposing GPCD requirements on anyone but
    individual users.                As we have noted above, A.R.S. § 45-565.01(H)
    effectively dooms any such argument, by stating that a municipal
    provider who applies for an NPCCP is not exempted from “per
    capita    conservation             requirements      established       under    §     45-565,
    subsection A, paragraph 2” until the application is approved.
    19
    This   statute      necessarily      assumes      that          §    45-565(A)(2)        is     not
    limited       to      authorizing     the         imposition            of     conservation
    requirements on individual users.
    ¶29           In short, the express language of the Code does not
    support the conclusion reached below that the SMP must include
    mandatory      conservation      requirements          imposed          directly         on     end
    users.       Indeed, the majority of the court of appeals effectively
    conceded as much, suggesting instead that “common sense dictates
    that   if     one   is    assigned    the    duty          of       conserving      a    limited
    resource like groundwater, one needs the authority, and must
    assume the corresponding responsibility, to manage the resource
    throughout its entire cycle.”                    Ariz. Water Co., 
    205 Ariz. at
    537 ¶ 18, 
    73 P.3d at 1272
    .            The court of appeals therefore held
    that the statute required management of groundwater use by end
    users,       because     “legislative       enactments              [must]    be        given      a
    sensible construction.”           Id. ¶ 19.           While the legislature could
    have sensibly reached the conclusion that direct regulation of
    all    end    users      was   necessary,        it    also         could    have       sensibly
    concluded that the goal of achieving per capita reductions in
    groundwater use could be most effectively served by leaving to
    the discretion of the expert Director of ADWR the decision about
    whether      GPCD   requirements      should          be    imposed         directly          on   a
    relatively small number of providers, rather than on hundreds of
    thousands of end users.              “Common sense” could lead to either
    20
    conclusion, and thus provides no basis for concluding that the
    statute must have envisioned direct regulation of end users.
    ¶30         In circumstances like these, in which the legislature
    has not spoken definitively to the issue at hand, “considerable
    weight     should        be       accorded     to        an     executive       department’s
    construction     of          a     statutory        scheme       it    is     entrusted    to
    administer.”         Chevron,          U.S.A.,       Inc.       v.    Natural      Res.   Def.
    Council, Inc., 
    467 U.S. 837
    , 844 (1984).                               In such cases, “a
    court may not substitute its own construction of a statutory
    provision     for        a        reasonable        interpretation          made     by    the
    administrator       of       an    agency.”          
    Id.
            ADWR    has     consistently
    interpreted the Code as allowing it to impose GPCD requirements
    directly    on      providers          without           also    imposing       conservation
    requirements directly on all end users, and that interpretation
    should be given great weight in the absence of clear statutory
    guidance to the contrary.                See Long v. Dick, 
    87 Ariz. 25
    , 29,
    
    347 P.2d 581
    , 584 (1959) (holding that although administrative
    interpretation of statutes is not binding on the court, the
    court will accept an administrative body’s interpretation when
    there is “[a]cquiescence in meaning over long periods of time”
    so long as the interpretation is not “manifestly erroneous”).
    ¶31         Indeed, ADWR is “precisely the type of agency to which
    deference    should          presumptively          be    afforded.”          Fed.   Election
    Comm’n v. Democratic Senatorial Campaign Comm., 
    454 U.S. 27
    , 37
    21
    (1981).      The legislature mandated that the Director be an expert
    in    the   field.      See      A.R.S.    §       45-102(D)    (requiring          that    the
    Director      “be     experienced       and        competent    in     water    resources
    management      and         conservation,           and   .     .      .     have     proven
    administrative        ability”).          In   light      of    that       expertise,       the
    legislature gave the Director, known colloquially as the “water
    czar,”      Desmond    D.     Connall,     Jr.,       A   History      of    the     Arizona
    Groundwater Management Act, 
    1982 Ariz. St. L.J. 313
    , 333, broad
    powers to achieve groundwater conservation.                          See A.R.S. § 45-
    103(B)      (vesting        in    the     Director         “general          control        and
    supervision” of state groundwater).                       In cases like this, in
    which the statutory language is admittedly not dispositive,11 the
    Director’s expert interpretation deserves considerable deference
    by the judiciary, and should not be overturned simply because
    judges find a greater “sensibility quotient,” Ariz. Water Co.,
    
    205 Ariz. at
    537 ¶ 19, 
    73 P.3d at 1272
    , in an alternative
    interpretation of the statute.
    ¶32           In arguing against the Director’s interpretation, AWC
    contends     that     the    legislature       could      not   have        intended       that
    municipal providers be required to comply with GPCD requirements
    without also providing them with tools to enforce cooperation by
    11
    See Ariz. Water Co., 
    205 Ariz. at
    538 ¶ 26, 
    73 P.3d at 1273
     (“[W]e must agree with the Department that the legislature
    did not expressly order inclusion of end-user conservation
    measures in the Department’s management plans . . . .”).
    22
    end users.       But the legislature could have rationally concluded
    that the Director was in the best position to decide whether
    direct   regulation       of   end   users    in      any   particular         plan   was
    necessary to achievement of per capita conservation goals.                            In
    certain circumstances, such direct regulation may be the most
    efficient    method       of    achieving       the     desired         reduction      of
    groundwater use.      In others, “imposing conservation requirements
    on all end users who receive groundwater may do little to reduce
    total groundwater use,” and “[t]he resources devoted to creating
    and enforcing individual conservation requirements may be more
    effectively utilized in other ways.”                  
    Id.
     at 548 ¶ 82, 
    73 P.3d at 1283
     (concurring and dissenting opinion).
    ¶33         As    Judge   Irvine     noted,     “whether     it    is    sensible      to
    regulate end users is simply not addressed by the record before
    us and is completely beyond our expertise.”                  
    Id.
     at 547 ¶ 77, 
    73 P.3d at 1282
    .       Our job is statutory construction, and for the
    reasons set forth above, we hold that the Code left the decision
    about whether to require direct regulation of groundwater users
    to the discretion of the expert “water czar.”
    ¶34         Our conclusion is buttressed by the fact that neither
    AWC nor the courts below could articulate precisely what sort of
    regulation of end users would suffice under their view of the
    statute.     The    trial      judge,   after    rejecting        the    SMP    for   its
    failure to regulate end users directly, stated he did not think
    23
    that the Code required regulation of “each user or necessarily
    even for each category of user, but in some way we have to meet
    the    statutory       mandate      of   having    something    in     a    plan      that
    addresses the problem with an end user.”                    
    Id.
     at 549 ¶ 84, 
    73 P.3d at 1284
          (concurring     and     dissenting    opinion)         (quoting
    transcript of trial court proceedings).                  But the SMP at issue
    here did impose conservation requirements directly on some end
    users, see supra n.7, and the superior court failed to indicate
    how much more direct regulation was needed in order to comply
    with the Code.           The majority below provided no greater guidance
    as to what the Code required, simply directing the Department to
    “return       to   the    management      plan    drawing     board”       to    “devise
    appropriate conservation measures for its management plan that
    include end users.”           Id. at 538 ¶ 26, 
    73 P.3d at 1273
    .                  Because
    even    AWC    concedes      that    “faucet-by-faucet”        regulation        of    end
    users is not required by the Code, and because the SMP at issue
    does regulate some end users directly, it is not clear what
    “appropriate          conservation       measures”    the     court        of    appeals
    believes are mandated by the Code.12
    12
    As Judge Irvine observed:
    Arizona Water does not argue that the specific end
    user measures adopted by the Department are not
    “appropriate.”   If it made such an argument courts
    would have a statutory basis upon which to review the
    actions of the Department.   The trial court's order
    here, however, merely tells the Department to again
    24
    ¶35            In short, we conclude, as did the dissenting judge
    below,     that   while   the   Code   requires     the    SMP   to    provide   for
    reductions in per capita use of groundwater, the management plan
    need only impose such conservation measures that the Director
    concludes       are   “appropriate”      directly     on    individual       users.
    A.R.S.     §   45-565(A)(2).       The    Director    thus       had   the   facial
    statutory authority to promulgate an SMP that did not impose
    conservation measures directly on all of AWC’s end users.13
    _______________________________
    exercise its discretion to develop a management plan,
    but to do it better.       Its inability to be more
    specific is strong evidence that the language of the
    statute simply does not support its ruling.
    Ariz. Water Co., 
    205 Ariz. at
    549 ¶ 86, 
    73 P.3d at 1284
    (concurring and dissenting opinion).
    13
    AWC also argues, as it did below, that imposing
    responsibility on municipal providers to limit GPCD places
    providers in an impossible regulatory conflict between ADWR and
    the Corporation Commission because a public service corporation
    cannot unilaterally refuse to serve or curtail service to
    customers in its service area.    See A.R.S. § 40-321(B) (2001)
    (requiring public service corporations to render service “upon
    proper demand and tender of rates”). While arguing in the court
    of appeals that ADWR did not have the authority to tell AWC
    which customers it must serve or how much each customer could
    receive, the Commission took the position that there was no
    necessary conflict between its position and ADWR’s GPCD
    requirements, noting that “there is nothing to prevent Arizona
    Water from asking the Commission to allow it to curtail service
    in appropriate circumstances.”   Ariz. Water Co., 
    205 Ariz. at
    539 ¶ 28, 
    73 P.3d at 1274
    . The court of appeals thus refused to
    address AWC’s arguments on this point.   
    Id. at 538
    , 
    73 P.3d at 1273
    ; 
    id.
     at 544 ¶ 59, 
    73 P.3d at 1279
     (concurring and
    dissenting opinion).     We agree.     This case presents “no
    inevitable conflict between the jurisdictions of the Department
    and the Commission” and there is no need to today “address a
    25
    C.
    ¶36         For    each   municipal    provider    such      as   AWC,    ADWR
    establishes    a   GPCD   in   the   applicable   management      plan.    In
    analyzing compliance with the GPCD program, ADWR analyzes the
    provider’s water use under the “stacking” method.                 Under this
    method,
    the Department first counts against the provider’s
    total GPCD requirement, all water used by a water
    provider during the year, except for spillwater and
    effluent that is not recovered effluent.       Although
    water used by the provider during the year from such
    sources is counted when determining the provider’s
    compliance   with    its   total    GPCD   requirement,
    groundwater is counted last.      If the provider is
    determined to be out of compliance with its total GPCD
    requirement, the provider is out of compliance only to
    the extent by which the amount of groundwater used
    exceeds the provider’s total GPCD requirement.
    Ariz. Mun. Water Users Ass’n v. Ariz. Dep’t of Water Res., 
    181 Ariz. 136
    , 139-40, 
    888 P.2d 1323
    , 1326-27 (App. 1994) (“Water
    Users”) (footnote omitted).          Under this method, a provider who
    uses no groundwater is always in compliance with its GPCD, no
    matter how much water it uses from other sources.                 A provider
    who uses only groundwater is limited to the amount specified by
    the GPCD.     For providers using some combination of water sources
    including groundwater, ADWR will calculate the provider’s total
    water use (excluding spillwater and non-recovered effluent), and
    _______________________________
    speculative conflict.”          
    Id.
     at 544    ¶   59,   
    73 P.3d at 1279
    (concurring and dissenting opinion).
    26
    in the event of any excess over the GPCD, will consider the
    provider out of compliance with the management plan only to the
    extent the excess is attributable to groundwater.
    ¶37          AWC uses a combination of CAP water and groundwater to
    serve its Apache Junction customers.                Because the total amount
    of water used from these two sources exceeds the applicable GPCD
    limitations, ADWR has determined that AWC is out of compliance
    with the SMP.      As such, AWC is subject to various enforcement
    actions and penalties.          See A.R.S. §§ 45-634 to -636.
    ¶38          AWC contends that ADWR’s counting of CAP water in its
    “stacking” method is not authorized by the Code and is contrary
    to the Groundwater Act’s general policy of limiting groundwater
    use.   See A.R.S. § 45-107(C) (2003) (providing that the Director
    does not have authority to limit rights of various individuals
    and entities to contract with the secretary of interior for
    delivery   of    CAP    water).      The    court    of   appeals    unanimously
    rejected this argument.          Ariz. Water Co., 
    205 Ariz. at
    541-43 ¶¶
    47-52, 
    73 P.3d at 1276-78
    ; 
    id.
     at 543 ¶ 58, 
    73 P.3d at 1278
    (concurring and dissenting opinion).
    ¶39          AWC’s argument starts from the premise that the Code
    only authorizes ADWR to adopt conservation programs for “all
    non-irrigation     uses    of    groundwater.”       A.R.S.   §§    45-564(A)(2)
    (governing      first     management       plan),    -565(A)(2)     (containing
    identical language with respect to second plan).                    Because CAP
    27
    water is not groundwater as defined in A.R.S. § 45-101(5) (2003)
    (“water under the surface of the earth”), AWC contends that ADWR
    cannot count CAP water in determining whether a provider has
    complied with the GPCD, which is plainly a conservation program.
    See A.R.S. § 45-402(28)(a) (defining “[n]on-irrigation use” as
    “a use of groundwater other than an irrigation use”).
    ¶40          The Code is not as clear on the subject as AWC claims.
    The   same    sections      cited    by   AWC,   after        providing          that    the
    Director     may    establish     conservation        programs           for   “all     non-
    irrigation     uses    of    groundwater,”       go     on     to        require      “[f]or
    municipal     uses”     that    management       plans       include           “reasonable
    reductions     in     per   capita    use.”           A.R.S.        §§     45-564(A)(2),
    -565(A)(2).        In turn, A.R.S. § 45-561(11) defines “[m]unicipal
    use” as
    all non-irrigation uses of water supplied by a city,
    town, private water company or irrigation district,
    except for uses of water, other than Colorado river
    water, released for beneficial use from storage,
    diversion or distribution facilities to avoid spilling
    that would otherwise occur due to uncontrolled surface
    water inflows that exceed facility capacity.
    ¶41          Several     things     are   noteworthy         about        §    45-561(11).
    First, it occurs in the same article as §§ 45-564 and -565, and
    requires use of its definitions in that article “unless context
    otherwise requires.”           A.R.S. § 45-561.              Second, § 45-561(11)
    defines “[m]unicipal use” as extending to “all non-irrigation
    uses of water.”        (Emphasis added.)         If the legislature meant to
    28
    limit “municipal use” to “non-irrigation uses of groundwater,”
    it could have done so without adding the phrase “of water,”
    because A.R.S. § 45-402(28)(a) already defined “[n]on-irrigation
    use” as “a use of groundwater other than an irrigation use.”
    (Emphasis added.)         The use of the term “of water” thus suggests
    a   broader    scope   for      “municipal     use”   other    than   just   use   of
    groundwater.       Moreover,       the   balance      of   §   45-561(11)    plainly
    includes use of Colorado River water within the definition of
    “municipal use.”14
    ¶42           Given § 45-561(11), AWC’s argument must necessarily be
    that “context otherwise requires” that the term “municipal uses”
    in §§ 45-564(A)(2) and -565(A)(2) be interpreted as “municipal
    uses of groundwater.”           Put differently, AWC must be arguing that
    the first sentence of each subsection, which generally requires
    ADWR    to    establish        “conservation     requirements      for   all   non-
    irrigation      uses      of     groundwater,”        provides     the   necessary
    14
    In 1990, the predecessor of § 45-561(11) (then
    numbered § 45-561(6)) was amended to add the phrase “except for
    uses of water, other than Colorado river water, released from
    storage facilities into a surface water distribution system to
    avoid spilling.”   1990 Ariz. Sess. Laws, ch. 71, § 3.   As the
    court in Water Users pointed out, “if the term ‘water’ used in
    the original definition of ‘municipal use’ was limited to
    groundwater, the legislature would have had no reason to amend
    the   definition  of   ‘municipal  use’  to  expressly  exclude
    spillwater, a form of surface water.”    
    181 Ariz. at 142
    , 
    888 P.2d at 1329
    .       Water Users therefore concluded that the
    legislature meant, in defining municipal use, to include all
    other sources of water not specifically excluded.   
    Id.
     at 142-
    43, 
    888 P.2d at 1329-30
    .
    29
    “context”      for    concluding     that      the   requirement     in    the    second
    sentence that ADWR adopt conservation programs for “municipal
    uses” was only to such “uses” of groundwater.
    ¶43           There are two problems with such an argument.                       First,
    if the legislature really meant to limit the term “municipal
    uses”    in    §§     45-564(A)(2)       and     -565(A)(2)   to     such    uses      of
    groundwater, it could have said so expressly.                   See Water Users,
    
    181 Ariz. at 142
    , 
    888 P.2d at 1329
     (noting that throughout the
    Code the legislature used the term “water” when it meant to
    “refer    to     water       from   all     sources,”       versus    its        use    of
    “groundwater”          or    “surface       water”     when    it     intended         to
    “distinguish between different sources of water”).                        Second, this
    argument requires that we interpret the third sentence of each
    subsection,          which    mandates      conservation       requirements            for
    “industrial         uses,”    to    be    limited      to   industrial       uses       of
    “groundwater.”         But such an interpretation flies in the face of
    the definition of “[i]ndustrial use” in § 45-561(5) as “a non-
    irrigation use of water not supplied by a city, town or private
    water company.”         (Emphasis added.)
    ¶44           In addressing a similar issue, the court of appeals
    concluded in Water Users that the term “municipal uses” in § 45-
    565(A)(2) should be interpreted, consistent with its definition
    in § 45-561(11), as including all sources of water, including
    recovered effluent.           
    181 Ariz. at 142-43
    , 
    888 P.2d at 1329-30
    .
    30
    Water Users therefore concluded that recovered effluent could be
    counted under the “stacking” method in determining a municipal
    provider’s compliance with its GPCD requirements.                    We reach the
    same conclusion as to CAP water.
    ¶45           Moreover, even if we were to accept AWC’s contention
    that CAP water is not included in the phrase “municipal uses” in
    §    45-565(A)(2),   we   would    still       reach   the    same   result.    The
    “stacking” method does not restrict a municipal provider’s use
    of CAP water; any provider may use as much CAP water as it
    wishes.       Rather, ADWR simply takes use of CAP water and other
    surface water into account when determining the GPCD compliance
    of    those   providers    who    also    use    groundwater.         Because    the
    groundwater is counted last, the Department restricts only the
    use of that groundwater through the “stacking” method.                           See
    Water Users, 
    181 Ariz. at 141
    , 
    888 P.2d at 1328
     (concluding that
    even if ADWR had no authority to regulate effluent, counting
    recovered effluent under the “stacking” method “regulates only
    groundwater usage,” because non-compliance is measured not by
    how    much   effluent    was    used,    but    “only   to    the   extent    which
    groundwater use exceeds a provider’s total GPCD requirement”).
    III.
    ¶46           For the reasons above, we conclude (a) that ADWR has
    the statutory authority to impose GPCD requirements on municipal
    providers; (b) that the Code does not mandate that ADWR impose
    31
    conservation requirements on all end users before imposing GPCD
    requirements     on    municipal    providers;      and     (c)       that   ADWR    may,
    under   its     “stacking”   method,       consider       use    of    CAP   water     in
    determining GPCD compliance.
    ¶47           These    holdings    do     not    dispose        entirely     of     AWC’s
    claims.     Section 45-565(A)(2) authorizes only requirements for
    “reasonable     reductions    in    per    capita     use.”      (Emphasis        added.)
    AWC argued during the administrative proceedings below that the
    GPCD for its Apache Junction water utility was not reasonable,
    in light of various particular circumstances of that utility.
    The agency rejected this argument.                The superior court did not
    reach this claim, however, finding the SMP facially invalid for
    failure to impose direct regulation on all end users.                             Because
    it affirmed the judgment of the superior court, the court of
    appeals also did not reach the issue.                     Given that the courts
    below     did   not    address     AWC’s       argument    that        the   GPCD    was
    unreasonable      as   applied     to   the     Apache    Junction       utility,      we
    decline in the first instance to address that fact-intensive
    issue, but instead remand this case to the superior court for
    such other proceedings as may be necessary.
    32
    ¶48       The opinion of the court of appeals is affirmed in
    part and vacated in part, and the judgment of the superior court
    is vacated.   This case is remanded to the superior court for
    further proceedings consistent with this opinion.
    Andrew D. Hurwitz, Justice
    CONCURRING:
    _
    Charles E. Jones, Chief Justice
    ____________________________________
    Ruth V. McGregor, Vice Chief Justice
    _
    Rebecca White Berch, Justice
    _
    Michael D. Ryan, Justice
    33