Nonconforming uses and structures are governed by the regulations set forth in this chapter.

A lawful nonconforming use or structure may be continued; provided that no such use or structure shall be enlarged or increased, nor be extended to occupy a greater area than that occupied by such use prior to the date such use or structure became nonconforming. Nor shall a nonconforming use or structure be allowed to create a public health and safety hazard.

The nonconforming use of a portion of a building may be extended throughout the building; provided that in each case a use permit shall first be obtained.

The nonconforming use of a building may be changed to a use of the same or more restricted nature; provided that in each case a use permit shall first be obtained.

If a nonconforming use ceases for a continuous period of six months, it shall be considered abandoned and shall thereafter be used only in accordance with the regulations for the district in which it is located. If a nonconforming structure is more than fifty percent damaged by fire or otherwise ceases to exist, it can only be re-established in accordance with the code provisions applicable in the district within which it is located.

Ordinary maintenance and repairs may be made to any nonconforming building provided no structural alterations are made and providing that such work does not exceed fifteen percent of the appraised value in any one-year period. Other repairs or alterations may be permitted; provided, that a use permit shall first be secured in each case.

Expansion of a legal nonconforming single-family dwelling or duplex by not more than twenty-five percent of the floor area of the existing dwelling shall be permitted with the approval of the planning director. Such expansion shall meet all other requirements of this code and shall not result in the creation of more dwelling units than currently exists.