Ruby Mann went out three times in the past 35 years to vote against fluoridation of the city’s drinking water supply.

This week, she found herself among many San Antonians buying equipment to remove most of the mineral from their water.

On Thursday, fluorosilicic acid – a chemical containing the teeth-protecting mineral – began flowing through the pipes of the San Antonio Water System and the Bexar Metropolitan Water District.

The move came after 52.6 percent of the voters in a November 2000 referendum approved the addition of fluoride to the city’s drinking water. Voters had rejected it in 1966 and 1985.

Public water supply systems began adding the chemical to water about 50 years ago after studies showed it reduced the number of cavities in teeth. Still, some people don’t want it added to their water.

“I don’t want any of that stuff in my water because it’s nothing but poison,” said Mann, 82. “I don’t even want to give it to my dogs.”

Vendors of equipment to remove fluoride say business is booming.

“I haven’t been able to get off the phone,” said Allen Townsend, sales manager for Culligan Water Conditioning Co. “We have a tremendous number of calls. They’re wanting to know what they can do to take fluoride out of the water.”

He said the normal five to 10 calls a day has risen to 20 to 25 daily. Many of those are turning into sales and rentals, and Townsend’s six crews are busy installing the equipment.

The company’s under-the-sink model – which rents for $25 a month or costs $1,146 installed – produces up to 30 gallons of water a day, Townsend said.

A typical family uses no more than two to three gallons a day for consumption.

Reverse osmosis systems use a synthetic membrane filter to sift out tiny particles. They also employ carbon filters before and after the membrane filter.

The systems are designed to remove up to 98 percent of all minerals and contaminants in water, including about 90 percent of the fluorides.

SAWS spokesman John Boggess said the utility has been fielding 12 to 15 calls a day about fluoride.

“There’s been a whole range of questions,” he said. “People are concerned about any adverse effects on themselves, their fish, their pets, their plants.

“Only about 10 percent of the folks called to just vent because they were very angry about it,” Boggess said. “They’re not happy about having to buy these machines.”

Boggess said the utility notified the medical community about the change, primarily so that dentists who use fluoride and pediatricians who prescribe fluoride supplements can adjust their practices if necessary.

Local health officials say the mineral is not a cause for concern and that it will reduce tooth decay, especially among children. Still, some are not convinced.

“The interest in purchasing water treatment equipment has increased with the severe concerns of the general public,” said Hank Deutsch, owner of Biotech Water Researchers, which sells industrial, commercial and home water purification systems.

He said that the concerns led him to commission a manufacturer to make a countertop reverse osmosis system.

“For people who are renters or for people who just have a tighter budget, we have a countertop model that does a wonderful job, and it’s only $180,” he said.

At least one gallon of water is wasted for each gallon of water cleansed by household reverse osmosis units.