Navajo-Gallup Water Supply Project Amendments Act of 2023

This bill amends the Navajo-Gallup Water Supply Project Act to update definitions, expand the service area to include additional communities in New Mexico and Arizona, and establish a "Deferred Construction Fund" for delayed project facilities. It increases the authorized funding to $2.175 billion for fiscal years 2009-2029 and creates three trust funds to manage water resources development, operations/maintenance, and specific needs of the Jicarilla Apache Nation. The bill directly affects the Navajo Nation, Jicarilla Apache Nation, and the City of Gallup by changing how water infrastructure is funded, managed, and expanded. It updates environmental review terminology to "Final Environmental Impact Statement" and clarifies tax treatment for water facilities on tribal versus non-tribal land.