Mental Health Infrastructure Improvement Act of 2025

Creates a federal loan and loan-guarantee program to help plan, build, renovate, and expand pediatric and adult mental health and substance use disorder treatment facilities and related care capacity. The program sets eligibility, award priorities, loan terms (interest, maturity, fees), limits refinancing, and includes a pediatric set-aside and administration/enforcement roles for the Secretary and the Attorney General, with funding caps for fiscal years 2026–2030.

Establishes a dedicated Treasury trust fund to receive net revenues from the loan program (amounts above program costs). Those trust fund balances may be appropriated to support community mental health block grants under the Public Health Service Act, and remain available until expended.