A. 
Nonconforming uses. The nonconforming use of a nonconforming structure, building, premises, or fixture existing at the time of the adoption or any amendment of this chapter may be continued although it does not conform to the provisions of this chapter or any amendments thereto, but the alteration of, or addition to, or repair shall not exceed 50% of its assessed value of any nonshoreland existing building, premises, structure, or fixture for the purpose of carrying on a nonconforming use. The continuance of the nonconforming use of a temporary structure is prohibited.
B. 
Nonconforming structures. Repairs and maintenance of certain nonconforming structures: There is no limit based on cost for the repair, maintenance, renovation, or remodeling of a nonconforming structure.
C. 
Restoration of certain nonconforming structures. Nonconforming structures that are damaged or destroyed may be restored if the structure will be restored to the size, location, and use that it had immediately before the damage or destruction occurred, with no limit on the costs of the repair, reconstruction, or improvement if all of the following apply:
(1) 
The use of the building or structure which is nonconforming was not discontinued for a period of 12 months or more; and
(2) 
The damage or destruction was caused by a natural event, including but not limited to violent wind, vandalism, fire, flood, ice, snow, mold, or infestation.
If a nonconforming use is discontinued or terminated for a period of 12 months, any further use of the structure, land or water shall conform to the provisions of this chapter.
A. 
Additions and enlargements to an existing nonconforming building with a conforming use are permitted and shall conform to the established yard/setback, height, parking, loading, and access provisions of this chapter. The provisions of this section with respect to additions or enlargements are applicable only if the lot is served by public sanitary sewer or, if relevant, conforms to existing sanitary code requirements for private on-site sewage treatment systems (POWTS).
B. 
An addition to a principal structure located in the street yard or in the primary street yard on a corner lot or double frontage lot shall not project beyond the average setback of the principal structure on the abutting lot to each side of the property in question. An addition to an accessory structure located in the street yard or in the primary street yard on a corner lot or double frontage lot shall not project beyond the average setback of the accessory structure on the abutting lot to each side of the property in question.
In any district, any permitted or permissible structure may be erected on a single lot of record at the effect date of adoption or amendment of this chapter. This provision shall apply even though such lot fails to meet the requirements of lot area, lot width, or both, for the district in which the lot is located, as amended, as long as the lot lawfully existed on April 1, 1986.
Once a nonconforming use or structure has been changed to conform, it shall not revert back to a nonconforming use or structure. Once the Zoning Board of Appeals has permitted the substitution of a more restrictive nonconforming use for an existing nonconforming use, the substituted use shall lose its status as a legal nonconforming use and become subject to all the conditions required by the Zoning Board of Appeals.