The lawful nonconforming use of a structure or land, including but not limited to fences, parking and zoning setbacks, existing at the time of the adoption or amendment of this chapter may be continued although the use does not conform to the provisions of this chapter. However, only that portion of the land in actual use may be so continued, and the structure may not be extended, enlarged, reconstructed, substituted, moved or structurally altered except when required to do so by law or order or so as to comply with the provisions of this chapter.

If no structural alterations are made, a nonconforming use of a building may be changed to any use permitted in the same use district as that in which the use existing is permitted according to the provisions of this chapter, provided that when a use district is changed, any existing nonconforming use in such changed district may be continued or changed to a use permitted in the same use district as that in which the existing use is permitted, provided that all other regulations governing the new use are complied with.

Substitution of new equipment may be permitted by the Zoning Board of Appeals if such equipment will reduce the incompatibility of the use with the neighboring uses.

Termination. If such nonconforming use is discontinued or terminated for a period of 12 months, any future use of the structure or land shall conform to the provisions of this chapter.

Building destroyed by fire or other calamity. Where a building located in a district restricted against its use has been destroyed by fire or other calamity to the extent of not more than 50% of its fair market value, the same may be rebuilt, but where such a building is destroyed to the extent of more than 50% of its fair market value, a permit may be granted for its reconstruction within 12 months from the date of such fire or other calamity, except that any public utility located in a district restricted against its use shall be permitted to rebuild, alter or enlarge in any business or industrial district as the interest of the public demands. A nonconforming structure damaged or destroyed by violent wind, vandalism, fire, flood, ice, snow, mold or infestation after March 2, 2006, may be restored in accordance with the provisions of § 62.23(7)(hc), Wis. Stats.