It is the purpose of this chapter to provide for the regulation of nonconforming uses, buildings and structures.

This title establishes separate districts, each of which is an appropriate area for the location of the uses which are permitted in that district, and each of which is based upon the long range, comprehensive general plan. It is necessary and consistent with the establishment of these districts that nonconforming uses, buildings and structures which adversely affect the development and taxable value of other property in the district not be permitted to increase or expand in size. It is logical and reasonable, and in accordance with the authority delegated by the statutes of the State of California, that a limitation be placed upon the expansion of existing nonconforming buildings and structures.

The use of structure in this chapter includes any improvement upon land, other than the land itself, any part of which is above grade, and includes any sign, whether attached to or upon another structure or to or upon a building or whether affixed directly in the ground, and all such signs as are painted or otherwise applied directly upon the surface of a building.

Any nonconforming use, building or structure which existed lawfully at the time of the adoption of the ordinance codified in this chapter and which remains nonconforming and any such use, building or structure which becomes nonconforming upon the adoption of the ordinance codified in this chapter or of any subsequent amendments thereto, may be continued, subject to the regulations in this chapter.

The nonconforming use of land not involving a structure or building, or in connection with any building or structure thereon which is accessory to the use of the land, may be continued, subject to the following provisions:

Any building or structure which does not conform to the regulations of the district in which it is located may be continued, subject to the provisions of Sections 18.16.050 through 18.16.110.

No building or structure which does not conform to all the regulations of the district in which it is located shall be moved in whole or in part to any other location on the lot unless every portion of such building or structure is moved and the use is made to conform to all of the regulations of the district in which it is located.

Except as provided for in Section 18.88.085 regarding two-family dwellings in the R 5000 zoning district, a building or structure, all or substantially all of which is designed or intended for a use which is not permitted in the district in which it is located and which is destroyed or damaged by fire or other casualty or act of God to the extent that the cost of restoration to the condition in which it was before the occurrence exceeds 50% of the cost of restoration of the entire building new, shall not be restored unless the building or structure and the use thereof conforms to all the regulations of the district in which it is located. In the event such damage or destruction is less than 50% of the cost of restoration of the entire building no repairs or reconstruction shall be made unless such restoration is started within one year from the date of the partial destruction and is diligently prosecuted to completion.

A building, or structure or portion thereof, all or substantially all of which is designed or intended for a use which is not permitted in the district in which it is located, which is or hereafter becomes vacant and remains unoccupied for a continuous period of six months, shall not thereafter be occupied except by a use which conforms to the use regulations of the district in which it is located.

The nonconforming use of part of a building or structure, all or substantially all of which is designed or intended for a use not permitted in the district in which it is located may only be extended throughout the floor on which the use is presently located, but no changes or structural alterations shall be made except if such changes or structural alterations and the use thereof conform to all the regulations of the district in which the building or structure is located. Wireless telecommunication facilities co-located on legal nonconforming monopoles may be permitted subject to the provisions of Chapter 18.114.

The nonconforming use of a building or structure, all or substantially all of which is designed or intended for a use not permitted in the district in which it is located, may be changed to a use permitted in the same district as the nonconforming use which presently occupies the building or structure or a use permitted in a more restrictive district.

Single-family homes lawfully constructed with City permits and located in multifamily districts shall be exempt from the provisions of Section 18.16.050, Repairs—Alterations, 18.16.080, Restoration, and 18.16.100, Expansion.