In order to qualify for a loan to buy the median house in California ($470K), one would need an income of $109K. The median household income in the state is $53K, less than half of the needed amount. The 'income gap' is the difference: i.e. $56K.
The Bay Area has the biggest gap at $85K. The Central Valley has the smallest gap at $29K.
Horrifying numbers to juggle with.