This act revises the White Mountain Apache Tribe Water Rights Quantification Act of 2010, including by extending certain deadlines and establishing reporting requirements. (The quantification act approved the White Mountain Apache Tribe Water Rights Quantification Agreement, settling the tribe's water rights in Arizona. It authorized the design and construction of a rural water system to address the water infrastructure needs on the tribe's reservation.) Specifically, the act extends the enforceability deadline, from 2023 to 2027, for the Department of the Interior to publish a statement of findings required by the quantification act. In particular, the act repeals the settlement agreement on December 31, 2027, if Interior does not publish by December 30, 2027, a statement of findings that specified conditions have been fulfilled (including that funds necessary to construct the rural water system have been deposited into a specified subaccount). The act makes changes to cost indexing for the funds and subaccounts established under the quantification act, including by allowing adjustments for construction costs. The act also requires annual reports to Congress describing all expenditures and including additional information, such as progress and cost accounting on the planning, design, and construction of the Miner Flat Dam and any additional water supply facilities resulting from expenditures. Finally, the act establishes requirements for determining whether the rural water system is substantially complete. In particular, the rural water system shall be determined to be substantially complete if (1) the infrastructure is capable of storing, diverting, treating, transmitting, and distributing a supply of water as set forth in the final project design; or (2) Interior has expended all available funding and cannot complete construction due solely to the lack of additional authorized funding.