The constantly increasing number of communities fluoridating their water supplies has made the measurement of fluoride a routine analysis in many laboratories. Since strict control of the concentration of fluoride is required, and most of the currently used methods of analysis are sensitive to interferences commonly encountered in surface waters, better methods of analysis have been sought. It was determined that at least two were worthy of collaborative study: the fluoride electrode and the ion-exchange methods. The lanthanum alizarin complexone method also was investigated and found to be useful for high salinity waters but not for ordinary waters. In this report the results obtained on analysis of three water samples for fluoride by an electrode method, an ion-exchange method and a modified electrode method are compared.