Clean Water Infrastructure Financing Act of 2003

Requires architectural and engineering contracts to be awarded consistent with procedures under the Federal Property and Administrative Services Act of 1949 or an equivalent State qualifications-based requirement.

Directs the Administrator of the Environmental Protection Agency to assist States in establishing simplified procedures for small water systems to obtain assistance under the Act.

Requires revolving funds to be used only for providing assistance for activities which have as a principal benefit the improvement or protection of water quality of navigable waters. Makes revisions concerning uses of funds for: (1) innovative technologies; (2) administrative expenses; (3) small system technical, planning, and management assistance; and (4) financially distressed communities.

Revises requirements related to consistency with plans and eligibility of treatment works not considered publicly owned.

Requires States to make grants to financially distressed communities in any fiscal year in which the Administrator has more than $1.4 billion available for obligation and allows a State to give priority to such communities in making loans.

Directs the Administrator to provide technical and financial assistance to owners and operators of publicly-owned treatment works for: (1) inventorying critical treatment works assets; (2) evaluating the performance and condition of these assets; and (3) developing a plan for maintaining and replacing treatment works.

Reauthorizes appropriations for FY 2004 through 2008 for the revolving fund program.