> The Immigration and Nationality Act (INA) requires that the hiring of a foreign worker will not adversely affect the wages and working conditions of U.S. workers comparably employed. To comply with the statute, the Department's regulations require that the wages offered to a foreign worker must be the prevailing wage rate for the occupational classification in the area of employment.

The prevailing wage rate is defined as the average wage paid to similarly employed workers in a specific occupation in the area of intended employment.

https://www.foreignlaborcert.doleta.gov/wages.cfm

It's the law: https://www.foreignlaborcert.doleta.gov/wages.cfm