AZ SB1511

Modifies Arizona Revised Statutes section 45-462 regarding grandfathered groundwater rights and extinguishment credits in the Pinal Active Management Area (AMA).

Establishes calculation method for extinguishment credits through December 31, 2021: Type 2 non-irrigation rights multiply acre-feet by 100; irrigation and Type 1 non-irrigation rights multiply 1.5 acre-feet by irrigation acres by 100.

Implements declining credit schedule for extinguishments after August 31, 2018, reducing unused credits to 75% on year 6, 50% on year 11, 25% on year 16, and 0% on year 21 anniversary dates.

Changes groundwater allowance for assured water supply certificates filed on or after September 1, 2018 from ten times annual water demand to zero times annual water demand.

Requires director of water resources to adopt rules by January 1, 2019 for calculating extinguishment credits in Pinal AMA and directs recalculation of available groundwater for assured water supply determinations.