This bill authorizes the U.S. Section of the International Boundary and Water Commission, which manages water-related issues along the U.S.-Mexico border, to accept funding from both federal and non-federal sources to study, design, build, operate, or maintain wastewater treatment plants, water conservation projects, flood control structures, and related infrastructure. Any money the Commission receives under this authority must be deposited into its existing Treasury account and can be used until fully spent on these projects. To prevent excessive reliance on outside contributions, the bill caps at $5 million per fiscal year the amount of credit or reimbursement the Commission can give non-federal partners toward their required share of project costs. The Commission must also report annually to relevant congressional committees detailing how the accepted funds were used and what costs were incurred. This measure primarily affects border communities and local governments near the U.S.-Mexico border that rely on the Commission's water infrastructure projects, giving the agency more flexibility to partner with outside funders on needed improvements.