The board, upon payment of the fees provided in this chapter, shall issue special temporary permits to engage in water conditioning installation and repair as provided in this chapter to those applicants who furnish sufficient proof that they were engaged in such business on January 1, 1973. Such special temporary permits are retroactive to January 1, 1973, and expire thirty days after the date the second examination as provided under section 43-18.1-04 is given, but no later than July 1, 1974. The board may prescribe rules and regulations under which regular temporary permits may be issued which must be generally in accordance with section 43-18-15.