The Water Project Navigators Act directs the Secretary of the Interior, through the Bureau of Reclamation, to establish within 180 days of enactment a program that funds "navigator" positions to help communities plan and carry out water projects with multiple benefits, such as improving drought resilience, water quality, and access to clean drinking water. Eligible applicants include states, Indian tribes, local water agencies, conservation districts, and nonprofit conservation organizations located in Western states, Alaska, Hawaii, and Puerto Rico, and these navigators would provide services like grant writing, project management, and technical and engineering assistance. Grants or cooperative agreements would generally last up to three years, with a possible two-year extension, and the federal government would normally cover up to 75 percent of costs, though this share can be increased or the match waived for tribes, disadvantaged communities, and similar groups facing financial hardship. The Secretary must prioritize applications benefiting tribes, disadvantaged and rural communities, and projects with broad stakeholder support, while barring funds from being used to meet existing legal environmental compliance obligations. Federal spending on the program is capped at $15 million per fiscal year, and within five years the Secretary must report to Congress on the program's effectiveness in reducing water shortages and building capacity in underserved communities.