SDCL § 42-7-94: Decisions and orders in writing--Service on person affected.

Every decision or order of the commission shall be made in writing and filed with the executive secretary and preserved as a permanent record of the commission. Such decisions shall be signed by the chairman and attested by the executive secretary and dated. No decision or order of the commission shall be effective as to any person until a certified copy has been personally served or sent by certified or registered mail to such person.