This bill authorizes the International Boundary and Water Commission (IBWC) to accept funds from Federal or non-Federal entities for studying, designing, constructing, operating, or maintaining wastewater treatment, water conservation, and flood control works. These accepted funds will be deposited into a dedicated Treasury account and remain available until expended for the specified activities. The legislation includes important limitations, such as a $5,000,000 annual cap on reimbursement or credit towards non-Federal shares. It also strictly prohibits the Commission from accepting funds from non-Federal entities domiciled in, headquartered in, or having agreements with a "foreign country of concern." To ensure transparency, the IBWC is required to submit an annual report to Congress detailing the activities and costs associated with these funds.