The WIFIA application process is two phases:

Phase 1: Project Selection: EPA announces the amount of funding it will have available and solicits letters of interest from prospective borrowers. In their letters of interest, prospective borrowers demonstrate their project's eligibility, creditworthiness, engineering feasibility, readiness to proceed, and alignment with EPA’s policy priorities. Based on this information, EPA selects projects which it intends to fund and invites the prospective borrowers to continue to the application process. 

Phase 2: Project Review, Negotiation, and Closing: Each invitee must apply for its WIFIA loan. The WIFIA program conducts a detailed financial and engineering review of the project. Based on that review, the WIFIA program proposes terms and conditions for the project and negotiates them with the applicant until they develop a mutually agreeable term sheet and loan agreement. Prior to closing, the WIFIA program must receive approval from the Administrator or his designee and the Office of Management and Budget. At closing, the prospective borrower executes the credit agreement, which is the binding legal document that allows the borrower to receive WIFIA funds.

For more details on the application process, see the WIFIA Program Handbook.