S.D. Codified Laws § 3-12C-803
A contributing member who becomes disabled and who has acquired at least three years of contributory service or noncontributory service since the member's most recent entry into active status and prior to becoming disabled or was disabled by accidental means while performing usual duties for an employer, is eligible for a disability benefit if the disability is expected to be of long, continued, and indefinite duration of at least one year. In order to be eligible for a disability benefit, a member must be disabled on the date the member's contributory service ends. Any member who fails to file an application for disability benefits with the executive director within three years after the date the member's contributory service ends, forfeits all rights to disability benefits. Any information required for a complete application must be received within one year after the application for disability benefits was received. If the required information is not received by the system within one year after the application is received, the member may reapply. For purposes of this section, a transfer within a participating unit, or a change in employment from one participating unit to another participating unit if there is no break in contributory service, does not constitute a new entry into active status. The provisions of this section apply to any member whose application for disability benefits is received by the system before July 1, 2015.
SDCL 3-12C-803