Clean Water Infrastructure Financing Act of 2003

Clean Water Infrastructure Financing Act of 2003 - Amends the Federal Water Pollution Control Act to remove certain requirements for States with respect to construction of treatment works under capitalization grant agreements.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 that have as a principal benefit the improvement or protection of water quality of navigable waters.Provides for an extended repayment period and additional subsidization with respect to loans made to financially distressed communities from revolving funds.Reauthorizes appropriations for FY 2003 through 2007 for the revolving fund program.