Public Charge is a general term for an individual who is indigent or sick person who must be taken care of at public expense. Liable to become a Public Charge is the term used in the United States to classify prospective immigrants who are denied entry due to their lack of sustainable living means.
A long-standing Immigration and Nationality Act (INA) public charge provision at INA 212(a)(4) establishes that applicants for a visa, admission, or adjustment of status are inadmissible to the United States if they are likely at any time to become a public charge. INA 212(a)(4) does not directly reference nonimmigrant applications for extension of stay (EOS) or change of status (COS), because they are not applications for a visa, admission, or adjustment of status. Agency policy guidance established by legacy INS in 1999 has therefore generally applied a formal INA 212(a)(4) review only to applicants for adjustment of status to permanent residence and in some cases, whether an alien is deportable on public charge grounds. See INS field guidance, published at 64 FR 28689 (May 26, 1999). That policy also narrowly defined “public benefits” to exclude past receipt of non-cash benefits (other than institutionalization for long-term care) or past receipt of special-purpose cash benefits not for income maintenance.
Every nonimmigrant seeking admission or extension or change of status must satisfy the inspector or adjudicator that he or she is capable of maintaining status and will not become a public charge. Therefore, international students and scholars are required to document sufficient sources of funding to cover tuition, fees and living expenses in order to be sponsored for the F-1 or J-1 status. They are also required to demonstrate sufficient private funding at the point of visa application so they will not become a public charge while in the U.S. especially because options for employment or for earning income to support these expenses are so limited in these categories.
Please see more details on the USDHS Public Charge Fact Sheet.