The crews at the San Marcos Water Treatment Plant have stopped adding fluoride to the city’s water supply, following the will of city voters who approved a referendum Nov. 3 to halt the practice.

The Guadalupe-Blanco River Authority, which runs the water plant, stopped adding the fluoride on Thursday. It will take a few days for the additive to be completely gone from the city supply, officials said.

“To be clear, the water supply has some naturally occurring fluoride. However, we will not put additional fluoride into the supply,” Jerry Sharp, manager of the San Marcos water treatment plant, said in a statement.

“Residents should not experience any change to the water’s taste or odor,” added Tom Taggart, head of the city’s Water-Wastewater Utility Department.

Taggart said San Marcos has been “working expeditiously” on the transition since last week’s election, in which nearly 61 percent of San Marcos voters approved a referendum to halt fluoridation.

Sam Brannon, organizer of the Fluoride-Free San Marcos Coalition that pushed for Proposition 1, said he is ecstatic about how quickly the measure is taking effect.

“From the minute they stop putting (fluoride in the water), it’s a positive effect on people because we’re no longer being poisoned by hazardous waste,” he told the University Star, the student newspaper at Texas State University.

Fluoride critics claim the additive causes an array of health defects when consumed in drinking water. Most health officials, however, have said that the widespread adoption of fluoridation following World War II is a success story that has greatly improved dental health and that fears of health defects are based on shaky science.

Putting an end to fluoridation in San Marcos may affect other water customers as well. The San Marcos water plant sends water into a pipeline along Interstate 35 that serves several other cities and utilities, including the cities of Kyle and Buda, the Sunfield development, the Goforth Special Utility District and Monarch Water.

San Marcos officials have notified the Texas Commission on Environmental Quality (TCEQ) and plan to work with any of the municipalities that want to maintain the addition of fluoride in their respective water supplies by retrofitting their points of service with equipment acquired and installed through a state grant program.