S.D. Codified Laws § 13-43-6.3
Until a teacher is in or beyond the fourth consecutive term of employment as a teacher with the school district, a school board may or may not renew the teacher's contract. The superintendent or chief executive officer shall give written notice of nonrenewal by April fifteenth but is not required to give further process or a reason for nonrenewal.
After a teacher is in or beyond the fourth consecutive term of employment as a teacher with the school district, §§ 13-43-6.1 and 13-43-6.2 apply to any nonrenewal of the teacher's contract. On or before April fifteenth, the superintendent or chief executive officer shall notify the teacher and the school board in writing of the recommendation to not renew the teacher's contract.
Acceptance by the teacher of an offer from the district to enter into a new contract with the teacher shall be in the manner specified in the offer. Failure of the teacher to accept the offer in the manner specified constitutes the termination of the existing contract between the teacher and the district at the end of its term.
SDCL 13-43-6.3