You don't even need to bring Prop 13 into the discussion. Depending upon both existing demographics of a town and the expected demographics of a new project, the development can lead to tax increases. Because, in many cases (especially outside of cities) most property taxes go to the schools, a development catering to young families is going to put a lot of pressure on an existing tax base in a community tending toward singles and couples with their kids off to college and beyond.