Since I am new to CRA, is a revolving line of credit to a municipal sewer authority reportable on CRA? If so, is this considered a Small Business Loan?

No- the definition of "small business loan" is defined by the definition in the Call Report instructions under "loans to small businesses.", at Schedule RC-C, Part II. This defines loans from Schedule RC-C, Part I items 1E 4A and 4B as being small business. Municipal loans go under item 8, "obligations of states and political subdivisions in the US" (to include sewer districts).

Jayc, you might look to see if it can be a CD loan. Depending on the Municipality, it may qualify.