New, lower fluoride standards will save the state’s water treatment plants about $400,000 a year, according to the Department of Environment and Natural Resources.

The additive is intended to prevent tooth decay and has been added to most municipal water systems in South Dakota for decades, based on federal recommendations.

The standard for how much fluoride ought to be added to prevent tooth decay changed at the federal level this April, however, after a yearslong comment period.

The adoption of the old standard in 1962 meant water systems were to aim for an optimal dose of 1.2 parts per million. Since then, however, toothpastes in the U.S. have become more useful in battling tooth decay.

“There’s more toothpaste that’s readily available with fluoride in it, so (the higher standard) wasn’t as necessary,” said Mark Mayer, the administrator of the DENR’s drinking water program.

The new standard aims for an optimal dose of 0.7 parts per million, and the two public comments the DENR took on the proposed rule changes were from people who opposed the fluoridation of water altogether, Mayer told the legislature’s rules review committee last week.

Worries about fluoridation have been around since the adoption of fluoride standards and continue to simmer nationwide, in spite of widespread support for fluoridation by dentists and the medical community.

Voters in Wichita, Kansas, rejected fluoridation in 1964, 1978 and again in 2012, as doctors and dentists pressured the city to either adopt fluoride standards or put the issue to a vote.

In South Dakota, controversies have not reached so fevered a pitch. The rules review committee voted 6-0 to adopt the new DENR rules.

In Sioux Falls, that means the bill for fluoridation will be cut approximately in half, according to Purification Plant Manager Tim Stefanich.

Fluoride, chlorine and ammonia – the latter two of which combine to form chloramines – are the only chemicals added to Sioux Falls’ water supply before it leaves the plant. The remaining chemicals, such as lime, are added during the purification process and are left behind as the water is pumped out.

The city’s bill for fluoridation already has dropped significantly in recent years. Since 2012, the city has collected a larger share of its water supply from the Lewis and Clark Regional Water System. That water is purified in Vermillion, and fluoride is added before it gets to Sioux Falls. The cost of bulk fluoride has dropped, as well.

Taking Lewis and Clark Water cut the fluoridation bill from about $100,000 a year – about $14.75 per million gallons – in 2011 to $43,000 a year in 2014. That lower bill will be cut in half, Stefanich said.

There are several water supplies statewide, particularly those surrounding the Missouri River, that have high levels of naturally occurring fluoride. Before the change, 11 of the state’s 77 regulated water systems didn’t need to add fluoride. With the change, that number jumps to 25, Mayer said.

“It’s going to save everybody money, but some people will be able to stop fluoridating altogether,” he said.

Fluoride cost per year in Sioux Falls

2011: $106,430/$14.64 per million gallons
2012: $105,909/$14.73 per million gallons
2013: $52,692/$10.40 per million gallons*
2014: $43,076/$11.14 per million gallons
2015 (ytd): $28,640/$9.48 per million gallons

* In 2012, the city began purchasing more fluoridated water from the Lewis and Clark Regional Water System

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