Both male and female bathrooms should have a "physically safe, sanitary and appropriate" place to change a nappy.
Known as the Bathrooms Accessible in Every Situation (BABIES) Act, it was first raised back in April by Congressman David N Cicilline.
"Federal buildings are paid for by taxpayers," he says.
"It's important to ensure that they are as open, as accessible, and as family-friendly as possible."