S.D. Codified Laws § 6-1-20
Any public hearing or meeting conducted by an elected or appointed municipal, county, or township officer regarding a quasi-judicial matter as defined in subdivision 1-32-1(10) may be conducted informally to secure the information required to make a decision. The formal rules of procedure and evidence do not apply to the conduct of the public hearing or meeting. If an officer relies upon any evidence not produced at a public hearing or meeting, the officer shall disclose the evidence publicly and include the information in the public record to afford all parties an opportunity to respond or participate. Failure to make this disclosure may be grounds for the municipal, county, or township officer's disqualification for that particular decision, pursuant to the grounds for disqualification pursuant to § 6-1-21.
SDCL 6-1-20