Wis. Admin. Code NR § 115.01
Section 281.31, Stats., provides that shoreland subdivision and zoning regulations shall: "further the maintenance of safe and healthful conditions; prevent and control water pollution; protect spawning grounds, fish and aquatic life; control building sites, placement of structure and land uses and reserve shore cover and natural beauty." Section 59.692, Stats., requires counties to effect the purposes of s. 281.31, Stats., and to promote the public health, safety and general welfare by adopting zoning regulations for the protection of all shorelands in unincorporated areas that meet shoreland zoning standards promulgated by the department. The purpose of this chapter is to establish minimum shoreland zoning standards for ordinances enacted under s. 59.692, Stats., for the purposes specified in s. 281.31(1), Stats., and to limit the direct and cumulative impacts of shoreland development on water quality; near-shore aquatic, wetland and upland wildlife habitat; and natural scenic beauty. Nothing in this rule shall be construed to limit the authority of a county to enact more restrictive shoreland zoning standards under s. 59.69 or 59.692, Stats., to effect the purposes of s. 281.31, Stats.
Wis. Admin. Code Department of Natural Resources § NR 115.01
Effective April 17, 2012, 2011 Wisconsin Act 170 created s. 59.692(2m), Stats., which prohibits a county from enacting, and a county, city, or village from enforcing, any provision in a county shoreland or subdivision ordinance that regulates the location, maintenance, expansion, replacement, repair, or relocation of a nonconforming building if the provision is more restrictive than the standards for nonconforming buildings under ch. NR 115; or the construction of a structure or building on a substandard lot if the provision is more restrictive than the standards for substandard lots under ch. NR 115.
2011 Wisconsin Act 170 also created other provisions that affect how a county regulates nonconforming uses and buildings, premises, structures, or fixtures under its general zoning ordinance.