Firstly the emitter was placedjust below the shower head:
They were then set to directional so that the particles fell as so:
In order to make them look more realistic, I added Gravity to effect the particles so they fell in more of an arc rather than in a straight line.
However, the particles still went through the bath, so I selected the particles and the bath and made it so that they collide.
The videos show the effects of the collision, and I have been having a bit of trouble with getting the particles to behave themselves.
I tried changing some of the settings and deleting the second set of particles that appeared, but the first set still goes through the bath a little bit. I do not think this would matter in an environment with a floor for example if this was in a bathroom there would be a plane underneath that would hide it going through. I may do a bit more testing on this tomorrow or over the weekend to see if I can improve it.