A little recent history: In 2012, California began unwinding its redevelopment agencies, the local investment organizations tasked with revitalizing “blighted” areas across the state. By law redevelopment agencies were supposed to provide a guaranteed stream of cash to cities for subsidized housing—20 percent of any increase in property tax payments.

Much—in many cities, most—of that money didn’t end up going into the construction of new housing, but was instead siphoned off to pay for broadly defined “administrative activities.” Still, with the end of redevelopment came the end of the single largest source of non-federal money for affordable housing in the state. California lawmakers never plugged that hole.

In the meantime, temporary influxes of cash from recent bond initiatives, Proposition 46 (2002) and Proposition 1C (2006), are nearly depleted. Excluding the Low-Income Housing Tax Credit program, between 2008 and 2014, state and federal funding for affordable housing development in California has dropped by more than $1.7 billion, or 66 percent.

California lawmakers have made some recent headway in scrounging up public dollars for subsidized housing. Passed last summer, a new $75 fee on home refinancing and other real estate transactions will generate more than $200 million annually for low-income housing. And a $4 billion affordable housing bond measure will be on the ballot this November.

That funding is just a drop in the bucket, considering the sheer number of low-income Californians who can’t afford their rents. The Legislative Analyst’s Office has estimated that it would cost an additional $15 billion to $30 billion each year for the state to provide subsidized housing to those who are most in need. Even in California, $15 billion is a lot of money.

Wouldn’t simply adding more market-rate housing make all housing more affordable? Eventually. But according to one UC Berkeley study, it can take decades before new supply begins to push down rents on the cheapest places. In the meantime, it found, subsidized housing is twice as effective as new private development at allowing low-income residents to weather rising rents and stay within a region.