I am assuming you mean a big water fountain, like you would find in a park. You can get decent results doing something like the following:
The water in the bowl/base of the fountain can be created using Fractal Noise and Colorama on a solid, tweaked to your taste and animated with the use of evolution, sub offset, etc.
The spray of water can be done with Trapcode Particular using the sphere emitter. There are many settings to tweak here, but the main ones fall in the Emitter, Particle, and Physics / Air categories. Multiple instances of particular work well for each section of fountain spray.
There are a number of ways to show the water spray hitting the bottom pool of water, such as a combination of ripple, CC drizzle, ...even caustics. Good lighting will help the realism of this.