It's the debate Calgary seems doomed to have over and over.

Calgarians have been asked five times whether they wanted fluoride added to their drinking water. They voted against adding it in 1957, 1961 and 1971, then in favour in 1989. It was being added at a level of 1.0 mg/L by 1991. In a 1998 plebiscite, they voted to continue adding fluoride to the water. Then, in 2011, city council voted to take it out.

Coun. Jeromy Farkas said that doesn't sit well with him.

"In my mind, it was not legitimate for council to unilaterally stop water fluoridation given that the precedent is that it was brought in through a plebiscite," said Farkas.

"Similar to that, I don't think council should unilaterally bring it in without consulting Calgarians."

To prepare the ground for a discussion, Farkas asked administration on Tuesday to pull together a briefing for council on the long background of the issue. He also wants information on the potential costs.

A small amount of fluoride still occurs naturally in the Bow And Elbow rivers, varying from about 0.1 and 0.4 mg/L throughout the year.

Councillor convinced of health benefits

When fluoridation ended in 2011, it cost about $750,000 annually to add it to the city's drinking water at the Bearspaw and Glenmore water treatment plants.

At that time, the city was also on the verge of having to spend more than $6 million to upgrade its fluoridation systems.

Farkas said, like public health officials, he's convinced of the benefits of fluoridation.

"Water fluoridation is one of modern society's premiere innovations in health science," he said.

But he said Calgarians would have to show support for the idea of putting this to another plebiscite, which he thinks could coincide with the 2021 municipal election.

Farkas said his office has been getting questions from constituents who want the city to revisit council's decision to stop adding fluoride.

The city held plebiscites on fluoridation in 1957, 1961, 1971, 1989 and 1998.