No temporary or mobile office shall be erected, established, maintained or operated in any zone until a conditional use permit has been obtained as provided in Chapter 18.72 of this title. A conditional use permit for a temporary or mobile office used in conjunction with an industrial or commercial operation shall be issued only within the industrial commercial (M-C) zone and in conjunction with the sale of cars or other facilities as deemed appropriate by the Planning Commission. Such offices shall be placed on a permanent foundation and shall be served by City services which may include water and sewer as required by the Planning Commission.

A real estate sales office in tract or a mobile real estate sales office in tract may be established in a residential development for the initial sale of property in that development only upon approval of a conditional use permit as provided in Chapter 18.72 of this title. A mobile real estate sales office in tract shall be removed immediately upon the sale of the last house or parcel in the tract. In no case shall the real estate sales office in tract or mobile real estate sales office in tract be used for such purposes for more than one year without further consideration by the Planning Commission and extension of the conditional use permit.

A real estate sales office out of tract may be established in a home located immediately adjacent to a residential tract under development for the initial sale of property in that tract, only upon approval of a conditional use permit as provided in Chapter 18.72 of this title. Such use shall terminate within 90 days following sale of the last house or parcel in the tract under development. In no case shall the real estate sales office out of tract be used for such purposes for more than one year without further consideration by the Planning Commission and extension of the conditional use permit.

A sales office associated with a Christmas tree lot may be established within a nonresidential zone for the temporary sale of Christmas trees only upon approval of a conditional use permit as provided in Chapter 18.72 of this title and provided that:

Upon approval of a conditional use permit as provided in Chapter 18.72 of this title, a mobile office or classroom may be erected on a permanent foundation in conjunction with the operation of an educational institution or facility.