Here is a list of communities that have openly rejected water fluoridation. If yours is not on the list then chances are you have fluoridated water. I have seen filtration devices that are specific to removing fluoride but never seen a source for a test kit specifically for fluoride.
The link below is for the community list but check out the rest of this website too, if there is a test kit, I think they will know. This is the most comprehensive website on water fluoridation I have seen.