May a municipality create two zoning districts that have identical uses but different setback, side yard, and etc. restrictions?
Yes. The zoning enabling statute only requires that zoning restrictions
be uniform within each zoning district and specifically authorizes
regulations in one district to differ from those in another. Wis. Stat.
sec. 62.23(7)(b). As long as there is some rational basis for the
different restrictions, a municipality may create two zoning districts
that allow the same land uses (e.g., single-family residential) but
impose different setback, side-yard, etc. requirements on the structures
allowed in each district. For example, a municipality might reasonably
decide to create a single-family residential zoning district for older
neighborhoods that allows the same uses as are allowed under an existing
single-family residential district classification but impose less
stringent setback and side yard restrictions in the older neighborhood
zone. A rational basis for the different classifications would be the
smaller lot sizes in the older neighborhood. One significant advantage
to this classification scheme would be a reduction in the number of
zoning variance requests for structures in the older neighborhoods.