Water Infrastructure Improvement Act of 2001

Water Infrastructure Improvement Act of 2001 - Amends the Federal Water Pollution Control Act to remove restrictions on grants for construction of publicly owned treatment works that limit: (1) use for secondary or more stringent treatment only; and (2) the amount that may be obligated for implementation of nonpoint source management programs and groundwater protection activities that will advance implementation of nonpoint source pollution control programs.

Authorizes appropriations for FY 2002 through 2006 for such grants and provides allotment rules regarding the grant formula, minimum percentage, the innovative projects set-aside, the reservation for bays and estuaries, and discretionary deposits in State water pollution control revolving funds.