The City of Toronto approved an inclusionary zoning (IZ) by-law that will go into effect in September of this year. IZ mandates that a percentage of residential space in new housing projects include affordable homes for low- and middle-income households. IZ can be a valuable zoning tool but there are problems with how it is being implemented in Toronto. Although it may well result in some new affordable housing units being developed, it will come with a cost for the city as a whole.