With the passage of 2011 Wisconsin Act 170, the state legislature made several significant changes to Wisconsin’s zoning laws with respect to nonconforming structures. The provisions in the new law went into effect on April 17, 2012. Many of the changes affect shoreland zoning, and some affect zoning in general.
With respect to shoreland zoning, the new law limits the ability of counties to be more restrictive than the DNR shoreland regulations, NR 115, for substandard lots and nonconforming structures. NR 115 sets minimum standards for such things as building setbacks, lot size, boathouses, etc.
With respect to shoreland and general zoning, probably the most significant change is that local (county, city, village or town) zoning ordinances “may not prohibit, or limit based on cost, the repair, maintenance, renovation, or remodeling of a nonconforming structure.” It is fairly common for zoning ordinances to limit repair, maintenance, renovation, and remodeling based on a 50% rule which had been the statutory rule until the enactment of the new law. Any such provision is now unenforceable.
Note that this does not say that no limits may be placed on the repair, maintenance, renovation, or remodeling of nonconforming structures. Only that such limits may not be based on cost.
Finally, the new law did not affect floodplain zoning, so presumably limits on repair, maintenance, renovation, or remodeling in floodplains based on cost remain valid.