Undocumented workers still pay tax.
https://en.wikipedia.org/wiki/Economic_impact_of_illegal_imm...
> The Institute on Taxation and Economic Policy released a report in February 2016, stating that 11 million undocumented immigrants in the United States are paying annually an estimated amount of $11.64 billion in state and local taxes, "on average an estimated 8 percent of their incomes."[25]