Rosalie Redenbaugh’s grandson is 4, an age when some health professionals believe ingesting fluoride promotes a lifetime of strong teeth.

But Redenbaugh could not have been happier with voters’ emphatic rejection Tuesday of Measure M, a proposal to add fluoride to Modesto’s water supply.

“I’m so thrilled that it failed,” she said Wednesday. “I didn’t feel like our water should be basically poisoned. I feel it’s something we should decide to give our children, not the government.”

But in a twist that even some Modesto officials did not see coming, next week’s City Council agenda includes a hearing on whether to take the procedural steps to begin fluoridating the city’s water supply.

Here is why: In May 2000, the council approved fluoridation. In June of this year, council members talked about whether to accept grant money to pay for the necessary equipment and whether to increase water rates to cover operating costs.

The debate ended with a council majority deciding to ask voters’ opinion of fluoridation — in an advisory ballot measure. The council would take up the grant and water rate issues after the election.

The council later decided to make the ballot outcome binding. If Measure M had passed, it would have required the city to take action on increasing water rates and accepting the equipment grant.

The measure did not include language that said the city would not fluoridate if it failed.

As a result, Measure M’s defeat puts the council back to where it was after a marathon hearing 18 months ago: The council approved fluoridation, but not a way to pay for it.

Wednesday, officials all but dismissed the possibility that the council would pursue fluoridation in the wake of Measure M’s shellacking. Only 39 percent of the voters favored fluoridation.

Councilman Mike Serpa said the no vote was “a pretty strong statement.”

Glen Lewis, engineering director, said his recommendation to the council will be “in alignment with the results of Measure M.”

Fluoridation supporters are dropping the matter. The $1 million in grants earmarked for Modesto will be offered to other communities.

State officials said Wednesday that they will not seek fines against the city for not fluoridating. Under a law that took effect in 1997, communities must fluoridate if money is available. No one has been punished, however.

“We could use that hammer if we chose to. But the department is not prepared to force fluoridation on anyone,” said Dr. David Nelson, who runs the dental health program for the state Department of Health Services.

In Redenbaugh’s neighborhood, many voters felt as she did. Her High Street-area precinct overwhelmingly opposed Measure M.

Cathy Richardson lives in an island of pro-fluoridation sentiment. She and a majority of voters in the neighborhood around Roseburg and Enslen avenues, supported Measure M.

The 22-year Modesto resident said she could not understand its defeat. “It just seems like it’s such a strong thing to vote for,” Richardson said. “I didn’t even think of voting the other way.”