Except as otherwise provided in this Title, uses of land, buildings or structures existing at the time of adoption of this Title or its predecessor ordinance may be continued although the particular use, or the building or structure, does not conform to the regulations specified by this Title for the district in which the particular building or structure is located or use is made. No nonconforming use may be extended to occupy a greater area of land, building or structure than is occupied at the time of the adoption of this Title.

   If any nonconforming use is discontinued or abandoned for a period of one year, any subsequent use of such land or building shall conform to the regulations specified for the district in which such land or building is located If any use is wholly discontinued for any reason except pursuant to a valid order of a court of law for a period of one year, it shall be conclusively presumed that such use has been abandoned within the meaning of this Title, all future uses shall comply with the regulations of the particular district in which the land or building is located.

   If no structural alterations are made therein, a nonconforming use or a nonconforming building may be changed to another use of the same or more restrictive classification upon the securing of a conditional use permit. If the nonconforming use is replaced by a more restrictive (less intensive) nonconforming use, the occupancy thereafter may not revert to a less restrictive more intensive use.

   Structural alterations including enlargement and extensions of any building or structure existing at the date of the adoption of this Title, if nonconforming in either design or arrangement, may be permitted only if such alteration is in compliance with the regulations set forth in this Title for the district where the building or structure is located. Any alteration which exceeds two hundred square feet in floor area shall require architectural review. The city planner may approve such alteration in the R-1 and R-2 zones. Alterations in all other zones require the approval of the planning commission as provided for in Chapter 17.121.

   Nonconforming structures may be maintained, repaired or portions thereof replaced upon securing the appropriate city approvals.

   A nonconforming building verified to have been destroyed to the extent of more than fifty percent of its reasonable value at the time of its destruction by fire, explosion, or other casualty or Act of God, may be restored, reconstructed and used only in compliance with the regulations existing in the district wherein it is located. Provided, however, that any single family R-1 nonconforming use may be rebuilt on it original foundation by only the owner-occupant at that time of destruction within a period of one year from the time of destruction, regardless of the percentage of destruction.

   The foregoing provisions of this chapter shall also apply, without limitation, to structures, land and uses which hereafter become nonconforming due to redistricting of any lands under provisions of this Title.