Yes, Flouride is classified as Toxic Waste and is poisonous. In fact, if a infant would eat a whole tube of toothpaste he/she would probably die due to the amount of Flouride.
That being said, Flouride protects the teeth and is important to maintain long term oral health. It is so important for the protection of your teeth that it is recommended to not rinse your mouth after you brush... or at least use a mouthwash with flouride after you brush and rinse to ensure that the flouride stays on your teeth.
There are still countries in the world that mixes small amounts of Flouride in the drinking water to get a population with better oral health.. but to add Flouride in the drinking water is really not recommended.
After all, water should be as clean as possible, and even though the amounts of Flouride is small... Flouride IS a poison and is NOT meant to be consumed.. In toothpaste and mouthwash that is spit out, yes. In water that you drink, no.