Supermarket Tax Credit for Underserved Areas Act This bill amends the Internal Revenue Code to: (1) increase the rate of the rehabilitation tax credit for a supermarket building placed in service after December 31, 2017, and before January 1, 2020, in an underserved area (i.e., any enterprise community or empowerment zone and any renewal community); (2) increase by $1,000 the limit on wages eligible for the work opportunity tax credit for employees of a supermarket located in an underserved area; and (3) allow a business-related tax credit for 15% of the gross receipts from the retail sale of locally grown fresh fruits and vegetables in a supermarket in an underserved area.