Grease traps may be omitted from temporary waste lines where these waste lines are required by the health officer and where they shall not be used for a period of more than 30 days. Requirements for separate laterals for each such temporary use shall be so interpreted that a number of these temporary uses may be jointly served by one lateral and be considered as one occupancy under the jurisdiction of the state fair and it shall be the responsibility of the state fair to keep this lateral open and free from obstruction. (Code 1941, Art. 96-6)