Agricultural users with grandfathered rights can accrue credits for unused groundwater and carry the credits over for future use. These credits have created a lien against the groundwater supply that, if used, could increase groundwater depletion and hamper the AMAs' ability to achieve safe yield. In 1997, credits in the Prescott, Phoenix, and Tucson AMAs totaled more than 6 times the total groundwater consumption of all users in these AMAs in 1995. The Code created eight types of groundwater withdrawal permits that allow users without a grandfathered right to pump groundwater. For categories related to mineral extraction and industrial uses, the Department must issue a permit if the applicant meets certain criteria and must renew it as long as the applicant continues to do so.
Provisions relating to the municipal sector also contribute to continued groundwater depletion.
For example, the Code's conservation requirements focus on the water provider, not on water users. However, these providers have little ability to control the amount of water used by their customers. The Legislature should consider forming a study commission to address the State's ability to achieve the safe yield goal. A study commission would allow input from water resource experts, civic leaders, and other important interests, such as municipalities, agriculture, and mining, that are impacted by the State's water resource policies. Although most of the State currently has a sufficient water supply, limitations in the regulatory structure may produce water supply concerns both now and in the future.