"Sadly I have seen this kind of 'BS' for far too many years," she wrote to Hamilton councillors.
"I am not talking about fluoride but hydrofluosilicic acid. Tooth decay is not a result of lack of fluoride but a result of too much sugar. And the DHBs should start addressing that issue.
"Maybe our DHB members can ask about hydrofluosilicic acid at their next meeting."
But the "extraordinary outburst" is another example of why decisions over water fluoridation should be made by district health boards and not local councils, Water New Zealand says.
Chief executive John Pfahlert said most councillors were not qualified to make decisions on fluoride in water because it was a scientific health issue, not an ideological one.
"It is totally preposterous for Hamilton City councillor Siggi Henry to claim that she knows more than scientists do about the benefits and risks of fluoride."
Pfahlert said calling scientists and health experts "smarty pants" shows an extraordinary level of childishness and ignorance from an elected representative.
"The facts around fluoride are very clear. Adding fluoride to drinking water poses no health risks at the recommended level of 0.7 to 1.0 parts per million while the benefits for dental health are irrefutable."
"I would sincerely hope that elected representatives of DHBs will take advice of health experts and the huge body of evidence supporting the case for fluoride in drinking water and that this will result in more communities in New Zealand benefiting from it.
The Government this year moved to shift responsibility for fluoridating water supplies from councils to DHBs to enable decisions about fluoride to be based on local health priorities.
Last week it introduced a Bill to Parliament to effect that transfer of powers.