... San Diego households on average pay 34 percent more for consumer goods and services each year than the rest of the country, mostly for life's necessities: shelter, healthcare, food, and transportation. Thus, true poverty in San Diego is greater than what the federal threshold presents...


...In 2006, more than 330,000 residents of San Diego County lived below the federal poverty level, which last year stood at $20,614 for a family of four...

If that is their reported income, then obviously that family of four has at least the same amount coming in under the table in order to survive.