In 1993, the legislature created a groundwater replenishment authority, Central Arizona Groundwater Replenishment District (CAGRD), to be operated by the Central Arizona Water Conservation District (CAWCD) throughout its three county service area. The purpose of the CAGRD is to provide a mechanism to assist landowners and water providers in demonstrating an assured water supply under the new Assured Water Supply Rules that became effective in 1995.

In 1993, the Arizona Legislature passed a law that provides an alternative method for subdivisions and water providers to meet the rules requiring a demonstrated 100-year supply of water. Entities that couldn’t otherwise demonstrate an adequate physical supply of renewable water supplies can pay the CAGRD a fee for the groundwater that the subdivision or water provider is “mining.” CAGRD takes responsibility for acquiring and replenishing water to offset the mined groundwater. Since “replacement” water does not have to be recharged in the same location as the withdrawal, localized groundwater declines are not prevented. However, the renewable water supply must be replenished in the same AMA where the members pumped, so it does meet the requirements of the goal of safe yield.

Under CAGRD within an AMA, the replenishment assessments paid are the same (per unit volume) for each of the contributing “members.” Members that are water providers pay the assessment directly to CAGRD. In the case of subdivisions enrolled as Member lands, each lot owner is a member and the individual pays in the form of an assessment on the property tax bill. To date, approximately 1100 subdivisions [127 in Tucson AMA] and 24 water providers [10 in Tucson AMA,] have applied for, or obtained, membership in the CAGRD.

Water used for replenishment may be CAP water or water from any other lawfully available source, except groundwater withdrawn from within an AMA. For the foreseeable future, the water that the CAGRD will use for replenishment will be excess CAP water. The excess CAP water supply was fully contracted in 2009, however, the CAWCD Board also adopted a policy that provided CAGRD with a priority to the use of up to 35,000 AF of excess CAP to meet replenishment obligations over the next 5 years as well as an additional priority to share up to 175,000 AF of excess CAP with the Arizona Water Bank.

In 1999, the legislature expanded CAWCD's replenishment authorities and responsibilities by passing the Water Sufficiency and Availability Act. This Act authorized the CAGRD to enter into agreements with member service areas seeking designations of assured water supply when sufficient groundwater is not physically available by requiring the replenishment of groundwater to be in the location where it is pumped.

Authority: CAGRD is a division of CAWCD, and is managed by the CAWCD Board. It is funded entirely by member fees.