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  • Writer's pictureMark L. Johnson

Know Your H2O-Part VI-Groundwater Management Act

Updated: Jul 11, 2021

Part VI provides the background on Arizona’s Groundwater Management Act (1980) and subsequent groundwater legislation/regulation that governs the use of groundwater in Arizona.

Now that we have the background on water resources, water rights and groundwater recharge, it is time to review the statutory requirements for groundwater in Arizona.

This has been a tough one to put together because of the complexities. Accordingly, this blog is longer than normal.

Many common water resource terms will be explained but you can go to the Water Lingo Tab for more definitions and information. Notes [1] containing references and supplemental information are provided at the end of the blog.


Groundwater Management Act

The Groundwater Management Act (GMA) was adopted in 1980 in response to; (1) aquifer overdraft concerns, (2) Central Arizona Project (CAP) utilization needs and (3) legal issues related to the Reasonable Use doctrine, i.e. transportation of groundwater from one parcel to another. [1][2][3]

GMA included the following key provisions:

  1. Active Management Areas (AMAs)

  2. Irrigation Non-Expansion Areas (INAs)

  3. Groundwater Rights & Permits

  4. Groundwater Management Plans

  5. Assured Water Supply Program

  6. Adequate Water Supply Program

  7. Groundwater Transportation

  8. Groundwater Storage, Recharge & Recovery

These key provisions are described in more detail below.

1. Active Management Areas

Active Management Areas (AMAs) where established in locations where groundwater overdraft concerns were the greatest. There are five AMAs; (1) Phoenix, (2) Prescott, (3) Pinal, (4) Tucson and (5) Santa Cruz. See map (below). The AMAs cover 80% of the population in Arizona. Each AMA is subject to the GMA (key provisions 3-8) described below.

2. Irrigation Non-Expansion Areas

Irrigation Non-Expansion Areas (INAs) are smaller areas that have insufficient groundwater supply to irrigate farmland but establishment of an AMA was not necessary. The irrigation of new land is prohibited and well owners are required to submit annual reports. There are three INAs; (1) Joseph City, (2) Harquahala and (3) Douglas. See map above.

3. Groundwater Rights & Permits

GMA established two basic groundwater rights within AMAs; (1) grandfathered rights and (2) non-grandfathered rights. A permitting system was also established to inventory and monitor groundwater withdrawals.

A key GMA provision is that groundwater cannot be utilized to irrigate new agricultural lands within an AMA.

Grandfathered Rights

Irrigation Grandfathered Right-reserves the right to irrigate specific parcels that had been irrigated with groundwater in the five years preceding GMA (1975-1980). The quantity is specified and cannot be sold, i.e. the right runs with the parcel.

Type 1 Right-the right to utilize retired irrigation water for non-irrigation use. The quantity is specified (cannot exceed 3 acre-feet/acre) and cannot be sold, i.e. the right runs with the parcel.

Type 2 Right-the right to use groundwater for non-irrigation purposes that had been used for non-irrigation purposes in the five years preceding GMA (1975-1980). The quantity is specified (cannot exceed maximum historical use) and can be sold apart from the parcel.

Non-Grandfathered Rights

Service Area Rights-provides cities, towns, private water companies and irrigation districts the right to withdraw groundwater to serve customers. Service area rights can be expanded to allow for growth with some limitations. Service area rights are subject to the AMA’s management plan provisions (see below).

Groundwater Withdrawal Permits-required for new groundwater uses within AMAs.

Exempt Wells-wells with a capacity of 35 gallons per minute or less only require a notice of intent to drill and can be used for non-irrigation purposes. Irrigation is allowed but only to 2-acres of land or less for growing crops for human or animal consumption.

4. Groundwater Management Plans

Each AMA has a specific Water Management Goal. The Goal of the Tucson AMA (TAMA) is to achieve safe-yield by 2025. Safe-yield is achieved when groundwater recharge (natural & artificial) is equal to or greater than groundwater withdrawal, i.e. no overdraft.

The Groundwater Users Advisory Council (GUAC) is five-member council appointed by the Governor (6-year term) to represent water users in the AMA. The GUAC collects input from local water users and advises the AMA Director (ADWR staff).

Management Plans are updated every 10 years (First-1980-1990, Second-1990-2000, Third-2000-2010, Fourth-2010-2020) and the Fifth Management Plan covers the period 2020-2025. The first four TAMA management plans are complete and work has begun on the Fifth Management Plan.

Each Management Plan is very comprehensive. The Management Plans develop strategies to meet the AMA Goal. The major strategies to achieve the Goal are water conservation and replacement of groundwater with renewable water supplies. Each plan includes the following sections: (1) Introduction, (2) Hydrology, (3) Water Demands & Supply, (4) Agriculture, (5) Municipal, (6)Industrial, (7) Water Quality, (8) Underground Storage, Savings and Replenishment, (9) Water Management Assistance, (10) Implementation, (11) Projected Water Budgets and (12) Water Management Strategy.

A future blog will summarize the TAMA Fourth Management Plan and Goal status.

5. Assured Water Supply Program

Real estate developments with 6 or more lots must demonstrate a secure water supply to serve the development and satisfy all current and future water demands for a period of 100 years, i.e. Assured Water Supply (AWS).

This can be demonstrated by; (1) obtaining a commitment to serve from a Designated Water Provider (public or private water utility) or (2) obtaining a Certificate of Assured Water Supply for the particular development.

Public and private water utilities can become Designated by demonstrating that they have the capacity to serve for 100 years. There are 35 public and private water utilities with AWS Designation in Arizona. Certificate applicants must prove the same.

The source of water must be renewable, e.g. Colorado River water, recycled wastewater, etc.

6. Adequate Water Supply Program

The Adequate Water Supply Program is for all the areas outside the AMAs. The process is the same for obtaining designation and certification in the Assured Water Supply Program. However, groundwater can be utilized to satisfy the 100-year source of supply criteria and if a developer cannot demonstrate the 100-year supply, they can still sell lots if they disclose!

7. Groundwater Transportation

Within AMA

  • Groundwater may be transported within an AMA sub-basin.

  • Groundwater transported across sub-basins or outside an AMA are subject to payment of damages.

Outside AMA

  • Reasonable Use doctrine applies

  • Groundwater may be transported within a sub-basin.

  • Groundwater may be transported across sub-basins.

  • Groundwater may not be transported outside a groundwater basin.

8. Groundwater Storage, Recharge & Recovery

The Underground Water Storage and Recovery Act (1986) and the Underground Water Storage and Replenishment Act (1994) augment the GMA and provided the legislation to utilize Arizona’s unused Colorado River supply by storing it underground and established the Groundwater Storage, Recharge and Recovery requirements.

Underground storage (see Part V) can occur by two methods:

  • Underground Storage Facility (USF)-portion of an aquifer where non-groundwater direct recharge occurs via spreading basins or injection wells.

  • Groundwater Savings Facility (GSF)-an entity (usually a farm) that practices indirect recharge (in-lieu recharge)

Entities that store water can recover that water in the same year. If they store more water than recovered they receive Long Term Storage Credits (LTSCs). The stored water can be recovered in the future anywhere within the AMA if the aquifer is not declining an average of four feet or more per year. ADWR keeps track of all this.

Any stored water that is not recovered in the same year is subject to a 5% cut to the aquifer, so the recovery is actually 95%. This takes into account evaporation and other losses and ensures the aquifer comes out whole. Recycled wastewater is not subject to a cut unless it is discharge into a river/stream where a 50% cut is applied.

The following table shows AMA Storage Capacity of GSFs and USFs. [3]


Arizona Water Organization

Before continuing with Groundwater Storage, Recharge & Recovery, it is essential to understand the Arizona Water Organization to make sense of all this. Please reference the chart below.

The Central Arizona Water Conservation District (CAWCD) was established in 1971 to; (1) manage and operate the Central Arizona Project (CAP) and (2) repay the federal government for the reimbursable costs of CAP construction. Reminder: CAP is the 336-mile aqueduct system that brings Colorado River water to Maricopa, Pinal and Pima counties. CAWCD is managed by a 15-member elected Board that serve staggered 6-year terms.

In 1993, the Arizona legislature gave CAWCD another duty; the responsibility to acquire water and replenish the aquifers in the three counties served by CAP. This became known as the Central Arizona Groundwater Replenishment District (CAGRD). To make matters more confusing, CAGRD is not actually a district! So we have one entity (CAWCD) responsible for both the major source of replenishment water (CAP) and the storage of replenishment water (CAGRD). Plus, the current President of CAWCD is also the Director of the Arizona State Land Department* which has morphed into a pro-development state land agency. All of this appears to be a huge conflict of interest! CAGRD looks more like a new form of heart-burn as you will see below!

The Arizona Department of Water Resources (ADWR) manages the GMA programs. Tom Buschatzke is the current Director of ADWR.

To complicate this further, the Arizona Water Banking Authority (AWBA) was established in 1996 to store Arizona's unused Colorado River entitlement. It is managed by a 5-member appointed Commission which is chaired by the ADWR Director. The AWBA acquires LTSCs via groundwater storage facilities that can be recovered during a shortage. The AWBA also stores water a few other purposes (see below).


Now back to Groundwater Storage, Recharge & Recovery.


The strict GMA provisions prompted entities without renewable water sources, i.e. water utilities without CAP allocation, real estate developers, etc., to push for a scheme to allow entities to obtain AWS status by promising to recharge in the future. CAGRD was created in 1993 as a sub-unit of CAWCD (see above) to fulfill this scheme.

CAGRD has two types of members; (1) Member Service Area (MSA) [public and private water utilities] and (2) Member Lands (ML) [subdivisions]. There are various requirements to become a member. Once a member, CAGRD agrees to recharge within three years any excess groundwater pumped by a member. This promise is how new subdivisions obtained AWS status and allowed accelerated growth in Arizona.

CAGRD members also pay fees. For an MSA, the utility pays fees to CAGRD and in turn assesses its customers via the water bill. For an ML, individual homeowners pay the fees via an assessment on the property tax bill.

Is CAGRD Arizona's Water Ponzi scheme? Recent newspaper articles and studies give one that impression. The Kyle Center for Water Policy at Morrison Institute-Arizona State University prepared a report entitled, "The Elusive Concept Of An Assured Water Supply-The Role of the CAGRD and Replenishment"[4]. I highly recommend reading it. Here are the key findings:

  • CAGRD is required to recharge in the same AMA from which the water is being withdrawn but has no obligation to recharge in the exact same location where the groundwater is being withdrawn. This defeats the AMA goal to eliminate overdraft.

  • CAGRD membership much greater than anticipated. Member land homes are expected to reach 383,000 by 2024. At the end of 2013, CAGRD membership inlcuded 263,707 land homes.

  • CAGRD's 2015 Plan of Operation [5] calls for an increase in replenishment obligation from the current 38,400 acre-feet per year (AFY) (2015) to 86,900 AFY (2034) and 113,000 AFY (2114). See Figure 4.1 below. Existing CAGRD long-term water supplies total 36,534 AFY. Therefore, 50,370 AFY is required to meet the 2034 demand and another 26,100 AFY to meet the 100-year demand in 2114. CAGRD utilizes short-term supplies (30 years or less) to meet some of this gap but it seems inconsistent when a 100-year supply is required for AWS status. In addition, CAGRD has identified a host of additional water supplies but many question the reality of the acquisitions. Finally, there is the ongoing long-term drought on the Colorado River which may not be adequately addressed in these projections.

  • CAGRD fees have increased dramatically. For example, TAMA replenishment assessment charges are now $746/AF. Plus there are enrollment/activation fees and annual membership fees.

  • AWS rules allow groundwater pumping levels to a maximum of 1,000 feet below land surface in TAMA. This amount of drawdown is excessive and could cause land subsidence and groundwater quality issues.


AWBA stores water to; (1) cover shortages on the Colorado River, (2) meet AMA goals, (3) tribal obligations and (4) interstate water banking. AWBA has purchased 4.3 MAF of LTSC for future use----3.7 MAF for Arizona and 0.6 MAF for Nevada. These LTSC are associated with recharge facilities throughout the AMAs. AWBA pays $211/AF for LTSC and the revenues to pay for LTSCs come from withdrawal fees, ad valorum taxes and general fund appropriations. [6]

The following chart shows 2016 non-groundwater deliveries to various recharge facilities in the Phoenix, Pinal & Tucson AMAs [3].

Both CAGRD and AWBA are subject to Arizona's Colorado River shortage sharing requirements from the 2007 Colorado River Interim Shortage Guidelines (up to 480,000 AFY) and the 2017 Drought Contingency Plan (up to 720,000 AFY).


  1. The Groundwater Management Act (1980) stopped the expansion of agricultural lands utilizing groundwater due to aquifer overdraft concerns and set the stage for an overly complex state-wide groundwater management system.

  2. Although Arizona has been engaged in Groundwater Storage, Recharge and Recovery for almost 40 years, the water supply situation is still tenuous.

  3. The Active Management Area (AMA) system is worthwhile but two AMA features defeat the purpose; (1) recharge can occur in areas distant from the withdrawal location and (2) drawdown up to 1,000' below ground surface is allowed.

  4. The Central Arizona Groundwater Replenishment District (CAGRD) scheme is based on a promise, i.e. pump groundwater today and maybe we will recharge in the future.

  5. CAGRD membership is much larger than anticipated and future water acquisitions to meet recharge obligations are considered skeptical.

  6. Both CAGRD and AWBA are subject to Arizona's Colorado River shortage cut-backs which could reduce Colorado River water deliveries up to 720,000 AFY.


Upcoming Parts include; Colorado River & Law of The River, Central Arizona Project, Tucson Active Management Area (TAMA), Marana Water/Tucson Water & Conclusions




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