City council's decision to to remove fluoride from Calgary's water supply followed years of debate on the subject. CBC

The city stopped putting fluoride into Calgary's drinking supply as of Thursday.

However, it will be at least a week before the fluoride drops back to naturally occurring levels, say city officials. Both the Bow and Elbow rivers naturally contain between .1 and .4 milligrams of fluoride per litre, depending on the time of year.

City council voted 10-3 in early February to stopping adding fluoride to the city's water at an estimated savings of about $750,000 a year, some of which will go towards improving dental health for children living in poverty.

Alderman Druh Farrell, who brought forward the motion to drop fluoride, described Thursday as long awaited.

"It's the culmination of many years of work and we've been through the discussion several times. Now we'll look at what to do with the residual funds, the $750,000 we would spend annually."

The city was also facing $6 million in upgrades to the Bearspaw and Glenmore water-treatment plants to continue with fluoridation.

The city needed authorization from Alberta Environment to stop putting fluoride in the water.

Two dentists, a doctor and Alberta Health Services urged Alberta Environment to reject the city's application, saying fluoride use prevents tooth decay. But an Alberta Environment spokeswoman said in April the concerns of the four intervenors were not accepted.