The proposals - which had the backing of former Health Secretary and Hull MP Alan Johnson and the British Dental Association - were mooted more than three years ago.
It was championed as the best way of tackling poor dental health by the former chairman of the health and wellbeing board Coun Colin Inglis, who retired this year, but was opposed by campaigners, the Lib Dem opposition and some Labour councillors.
Yorkshire Water is carrying out a Â£68,000 feasibility study, but Cabinet member Phil Webster said he would not countenance the spending of “one more penny on this foolhardy scheme” and there was “no appetite for it whatsoever.”
He said it was “too expensive, undemocratic and unproven,” adding: “I’ve always said I think it is forced medication by the State. To quote Monty Python the scheme is no more. I am in charge of finance and I can confidently say it won’t be happening.”
New health and wellbeing chairwoman Coun Hester Bridges said fluoridation was “unlikely,” given the lack of “overwhelming” evidence and “massive” opposition.
They also have to get East Riding Council to agree, as 87,000 residents would also get added fluoride.
She said: “If there was a groundswell of people demanding fluoride I think we would be giving it more consideration - but there isn’t. People are saying very clearly they want (to make) that choice.”
In a statement public health portfolio holder Coun Gwen Lunn said they were waiting for feedback from YW, regarding technical specification, timescales and costs. A report would then go to the council’s Cabinet.
The scheme was “just one element” of a plan, she said, including increasing breastfeeding rates and encouraging regular tooth brushing with a fluoride-based toothpaste.
She added: “Before any decision is made regarding fluoridation, a full public consultation will be undertaken”.
Around 5.8m people in England get fluoridated water - at a rate of around 1mg per litre - which is a level found to reduce tooth decay levels.
The city has the highest rate of tooth decay for children aged five in the region at 38 per cent and around 400 under 10s are admitted to hospital every year to have teeth removed under general anaesthetic.
A report by Public Health England in 2014 found on average that five-year-olds in fluoridated areas were 15 per cent less likely to have had tooth decay than those in non-fluoridated areas.