The Bay Area needs to build about 50,000 units a year between 2023 and 2031 to keep pace with its population but restrictive zoning has hindered development. A new study explored how much the restrictions are costing residents. The researchers found the “zoning tax” (what they called the difference between the actual cost of land and the cost without restrictive zoning) for one-quarter acre of land was $409,000. This is four times the median household income, which can make securing a mortgage difficult even for those well above the median income and nearly impossible for residents with lower incomes. This, in turn, affects renters, who now must compete with residents with high incomes, who are driving up rent prices. “It’s a very bad place to be poor, [and] it’s not a particularly good place to be middle-class,” said the study’s lead author, Joseph Gyourko.