A Congressional Budget Office report says it would grant 8 million people citizenship and those people would then pay taxes.
The report comes as a group of nuns reached the Bay Area on a mission for immigration reform.
They've traveled 6,500 miles across the country talking about the issue. They want to see the Senate bill pass, saying it's the moral and patriotic thing to do.
"All over this country we saw people are saying yes, we are standing up. We are better when immigrants are included. We saw immigrants giving back, we saw immigrants engaged. And just yesterday we heard from Silicon Valley because they need the creativity of immigrants," one woman Simone Campbell said.
The mission started at Ellis Island in New York and arrived at Angel Island in San Francisco Bay on Tuesday.