A study showed that a tourist fare on the Staten Island Ferry would bring in millions for the city. View Full Caption Flickr/InSapphoWeTrust

STATEN ISLAND — A $4 "tourist-only" fare on the Staten Island Ferry could bring in millions a year to the city, a study found.

The Independent Budget Office study, requested by Borough President James Oddo, found that adding the round-trip fare for non-Staten Island residents would raise $3.2 million in the first year and $35.3 million over 15 years, the Staten Island Advance first reported.

"It's small, but as a guy who's a veteran of 21 to 22 budgets, it's a significant amount of money," Oddo said.

"Any time we can raise a dollar in revenue without going to the New York taxpayers we have to consider it."

Anybody who is not a borough resident or who isn't traveling to work on Staten Island would be classified as a tourist.

The idea was originally floated in 2006, but with projects like the New York Wheel and Empire Outlets expected to increase ridership on the ferry, Oddo asked the agency to revisit the numbers. He said he's not actively pushing the idea, but wanted to get fresh data.

"We know a large increase in tourists using the Staten Island Ferry will happen, I was just curious about what that would shake out to," Oddo said.

"At this point it's just about having the conversation. It's not happening without a great deal of support amongst the public and Staten Island."

The ferry ride, which used to cost 50 cents per round trip before it became free in 1997, would only cost money for non-residents who travel between Manhattan to Staten Island.

Residents of the borough and people who work there would still ride free, and trips from Staten Island to Manhattan would also not cost anything, according to the study.

Oddo said riders would have a card to swipe proving they are eligible for free rides.