The lawful use of any land or building existing at the time of the adoption of this chapter may be continued although such use does not conform to the provisions of this chapter, and any such building may be reconstructed or structurally altered and the nonconforming use therein changed, subject to the following regulations:
A. 
Registration. All nonconforming uses shall be registered with the Zoning Enforcement Officer by the owner or agent within six months of the date of adoption of this chapter.
B. 
Additions. A nonconforming building or use shall not be added to or enlarged unless such nonconforming building or use is made to conform to the regulations of the district in which it is located.
C. 
Alterations. A building nonconforming as to use may not be reconstructed or structurally altered during its life to an extent exceeding in aggregate cost 50% of the fair value of the building, unless the use of such building is changed to a conforming use.
D. 
Changes. A nonconforming use may not be changed to another nonconforming use under the provisions of this section.
E. 
Discontinuance. Whenever a nonconforming use has been discontinued for a period of one year, any future use shall be in conformity with the provisions of this chapter. A reasonable interim, however, between tenants or occupants shall not be construed to mean discontinuance.
F. 
Restoration. A building nonconforming as to use which has been damaged by fire or other causes to the extent of not more than 50% of its fair value may be restored, reconstructed or used as before, provided that the bulk, height and area requirements shall not exceed that which existed before said damage. Said restoration must be completed within two years of such occurrence, or the use of the building or land as a legal nonconforming use thereafter shall be terminated.
G. 
Removal. If any building in which any nonconforming use is conducted is hereafter removed, the subsequent use of the land on which such building was located and the subsequent use of any building erected thereon shall conform to the regulations of the district.
H. 
Validity of permit. Any building for which a permit has been lawfully granted and on which the construction has been started and diligently prosecuted before the effective date of this chapter may be completed.