Calgary Mayor Naheed Nenshi says he would vote to add fluoride back into city drinking water if enough people rallied in favour.

"Based on the science that we've got, I would vote in favour of putting it back," Nenshi told a crowd of reporters at city hall on Monday.

A recent study conducted by the University of Calgary found that tooth decay in children has worsened since the city stopped fluoridating the water back in 2011.

Nenshi says he would like to see a bigger study, and take a closer look at more research on the subject, but he does trust the science that he has looked into so far.

Mayor Naheed Nenshi

Mayor Naheed Nenshi suggests people who want fluoride back in the city's drinking water should petition for a plebiscite. (CBC)

Nenshi says those who want city council to go back to adding fluoride can ask for a plebiscite to be held along with the next municipal election in 2017.

The city would have to receive support from 10 per cent of Calgary's population to get the process rolling, according to the Municipal Government Act. 

"If you were to put a petition on the front counter of every dentist's office, I suspect you'd get your signatures pretty quickly."

Nenshi was out of town for one of many votes held in 2011 to stop adding fluoride to the water.

He says he was in the minority when council voted to scrap adding flouride to the drinking water. He also clarified that he was actually present to vote when the bylaw passed that year.

But he said previously that since fluoride was added after a plebiscite in 1989, there should be public consultation before that decision was reversed.