S.D. Codified Laws § 12-17B-20
The post-election audit must be conducted in five percent of the precincts in the county by manually counting all votes cast in two contests and comparing the results of the manual count to the results for those precincts at the county canvass. The county auditor shall select the precincts for the audit at random without the use of a computer in public during the meeting of the county canvassing board. If the combined total of all ballots cast in the precincts selected does not exceed one hundred ballots, then additional precincts must be randomly selected until the total of all ballots exceeds one hundred ballots. For the purposes of this section, the term precinct includes vote centers, but does not include any precinct designated as an absentee precinct.
The county auditor shall select the contests for the audit at random without the use of a computer in public during the meeting of the county canvassing board. One contest randomly selected for the audit must be a statewide contest. If there are no statewide contests on the ballot, the auditor randomly shall select another contest on the ballot. If there is only one contest on the ballot, that contest must be audited.
SDCL 12-17B-20