The Western Water Infrastructure Fairness Act modifies federal funding rules for rural water infrastructure projects in the West by increasing the federal government's cost-sharing contribution for projects serving economically disadvantaged communities. Currently, the federal government covers a standard share of costs for these water projects, but this bill would raise that federal share to 90 percent specifically for projects benefiting economically disadvantaged areas, as defined under previous water development legislation. The change applies to rural water projects authorized under the Water Resources Development Act of 1999 and primarily affects Western states where water infrastructure needs are significant. The bill was introduced by Arizona senators Mark Kelly and Mark Gallego in July 2026 and referred to the Senate Committee on Energy and Natural Resources. No specific funding amount or implementation timeline is specified in the legislation text provided.