For all of Silicon Valley’s talk of embracing science, it’s stunning that much of the water supply in San Jose and Santa Clara County isn’t treated with fluoride — one of the most basic scientific advances in public health of the past century.

So it’s heartening to see that the Health Trust, with support from city and county officials, is launching a capital campaign to cover the estimated $18 million cost of fluoridating drinking water throughout the county.

Some areas already have fluoride, including Evergreen and other parts of San Jose served by the city’s municipal water system. But most of the city is served by the private San Jose Water Co., and it has not taken on the cost of fluoridating its water.

The project will be complex, since more than 100 wells are scattered throughout San Jose. And it will be controversial because of an extremely vocal minority who fight fluoridation whenever and wherever it’s proposed.

The scientific evidence of the benefits of fluoride is overwhelming, however — especially for children. Today one in every three kindergartners in Santa Clara County has untreated tooth decay that will likely lead to greater health problems and cause pain that interferes with early learning. Cities with fluoridated water report decreases in tooth decay of 18 to 40 percent.

From the national Centers for Disease Control to the local Santa Clara County Public Health Department, credible health agencies are strong proponents of fluoridation.

For far too long, San Jose has held the dubious distinction of being the largest city in the United States that doesn’t fluoridate its water. It’s past time to make that a bad memory.