California and many urban areas nationwide face a housing affordability crisis. New housing production has chronically failed to meet housing needs, causing housing prices to escalate. Faced with demands to “do something” about the housing affordability crisis, many local governments have turned to “inclusionary zoning” ordinances in which they mandate that developers sell a certain percentage of the homes they build at below-market prices to make them affordable for people with lower incomes. The number of cities with affordable housing mandates has grown rapidly, to about 10 percent of cities over 100,000 population as of the mid-90s, and many advocacy groups predict the trend will accelerate in the next five years. California was an early leader in the adoption of inclusionary zoning, and its use there has grown rapidly. Between 1990 and 2003, the number of California communities with inclusionary zoning more than tripled—from 29 to 107 communities—meaning about 20 percent of California communities now have inclusionary zoning.