In 1975 the Supreme Court ruled (in a decision commonly referred to as Mt. Laurel I) that municipalities have a constitutional obligation to enact zoning regulations that create a realistic opportunity for the development of the municipality’s fair share of affordable housing. The “Mt. Laurel Doctrine” essentially states that a community cannot zone in such a way to exclude low- and moderate-income households (i.e. have exclusionary zoning).
Examples of such “exclusionary zoning” include:
Single-family zoning with large minimum lot size requirements.
Minimum house size requirements which drive up the cost of housing construction and consequently, housing prices.
Prohibition of multi-family housing.
Limitation on number of bedrooms in multi-family dwellings to limit household sizes.
Prohibition of mobile homes.
Over-zoning for non-residential uses.