Fluoride prevents tooth decay and improves dental health, and is added to the water supply of western Lincolnshire.
Anglian Water will stop fluoridating water due to infrastructure work which will start in early 2024.
Lincolnshire County Council says it is exploring ways to minimise the impact.
Anglian Water have informed the Director of Public Health that the work is expected to last from early 2024 until March 2025.
During this time, the company would be unable to provide fluoride to just the areas of Lincolnshire which normally have it.
Since the eastern parts of Lincolnshire don’t have a legal agreement to receive it, the fluoride will have to be stopped for the entire county.
A report which went before the council’s Health Scrutiny Committee admits this is “likely to have a negative impact on oral health in the west of the county during this period of time.”
Anglian Water said that requests for fluoridation come from local health authorities and isn’t controlled by water companies.
The impact of fluoride can already been seen in tooth decay levels amongst Lincolnshire children.
Lucy Gavens, Public Health Consultant at Lincolnshire County Council, said: “Around 250,000 people are currently supplied with artificially fluoridated water in Lincolnshire.
“Fluoridated communities include Lincoln, Gainsborough, parts of Market Rasen and a large number of rural communities across the west and central areas of the county.
“Due to major infrastructure works planned for 2024 and early 2025 we are expecting that Anglian Water will temporarily stop fluoridating the water supply. Lincolnshire County Council is working with colleagues to explore ways to minimise the impact on dental health.”
The announcement comes as parts of Lincolnshire are experiencing a chronic shortage of dentists and long waiting lists.