From MA looking to see how i access the 2023 Schedule SC septic credit for repairing or replacing a failed septic system.

You will need to go most of the way through the MA state return until you get to the screen that says Massachusetts Credits.  On this page you will select Septic Credit.

TIR 97-12: Personal Income Tax Credit for Failed Cesspool or Septic System Title 5 Expenditures