Sunshine on Conflicts Act of 2013 - Amends the Federal Water Pollution Control Act (commonly known as the Clean Water Act) to require the Administrator of the Environmental Protection Agency (EPA) to issue a rule within 60 days to prohibit any member of a board or body that approves permit applications for the discharge of pollutants from seeking to influence the approval of any permit in which that member has a financial interest.

Provides that the requirement that state national pollutant discharge elimination system programs ensure that any board or body that approves permits excludes as a member any person who receives or has received during the previous two years a significant portion of income from permit holders or applicants shall have no force or effect after the earlier of the date on which such rule is issued or 120 days after this Act's enactment.