By Bill Silverfarb, San Mateo Daily Journal. With the economy in boom, San Mateo County has added tens of thousands of jobs in the past few years but only a fraction of the housing needed to accommodate them. With rents up 50 percent in four years to an average of more than $2,500 a month for a one-bedroom apartment, many low-wage earners can no longer afford to live in the county while a new glut of high-tech workers and other professionals can.