The Center for Immigration Studies (CIS) wrote in its Aug. 2004 article "The High Cost of Cheap Labor: Illegal Immigration and the Federal Budget" on

“[T]he net fiscal cost of immigration ranges from $11 billion to $22 billion per year, with most government expenditures on immigrants coming from state and local coffers, while most taxes paid by immigrants go to the federal treasury. The net deficit is caused by a low level of tax payments by immigrants, because they are disproportionately low-skilled and thus earn low wages, and a higher rate of consumption of government services, both because of their relative poverty and their higher fertility. This is especially true of illegal immigration. Even though illegal aliens make little use of welfare, from which they are generally barred, the costs of illegal immigration in terms of government expenditures for education, criminal justice, and emergency medical care are significant. California has estimated that the net cost to the state of providing government services to illegal immigrants approached $3 billion during a single fiscal year. The fact that states must bear the cost of federal failure turns illegal immigration, in effect, into one of the largest unfunded federal mandates.”

Aug. 2004