Undocumented Californians are, for the most part, left out of the health insurance system. Undocumented residents make up the largest group of Californians who lack insurance — approximately 1.5 million are projected to lack insurance in 2020. The uninsured rate for low-income undocumented adults is particularly high: 90 percent of undocumented California adults with household income at or below 138 percent of the Federal Poverty Level (FPL) lack insurance compared to 10 percent of all other California adults in the same income range in 2015-2016, according to findings from Six Facts About Undocumented Californians.

The rate of uninsurance for undocumented California adults is high for several reasons, including exclusion from full-scope Medi-Cal benefits under federal policy; ineligibility to buy insurance on Covered California because of immigration status; employment in industries/occupations that do not offer employer-sponsored insurance. Using CalSIM and other data, the study estimates 1.15 million undocumented in the state could gain health insurance in 2020 if the state expands Medi-Cal to all low-income adults regardless of immigration status, reducing uninsured population by as much as 25 percent.