If the water fountain is plugged in and it is a P’sik Reisha that drinking will turn on a motor, then it is Assur. Otherwise it’s okay. It depends on the water fountain.
In New York and other areas that have copepod issues, if the fountain is filtered, there may also be an issue of Borer. However, I have heard that R’ Schachter said there are 6 Tznifim L’hakel and not to worry about Borer in the water fountain.