It's not the water pump that's loud... It's how it's mounted and/or the pipes that are making all the noise... ;)
It probably has little rubber mounted feet on it, but if it's screwed down too tight and compressing those rubber feet, it's not doing any good.
If the outlet pipe from it is mounted directly to the floor, then that will cause the pipe to rattle and that's what you are hearing..
Try running the pump "dry" for a few seconds.. (no, it will not damage the pump)... Notice how quiet it is... It's not until it's pumping water and banging on the mounts and the pipes that is causing all the noise.
What I did was make sure the mount was not too tight. Then, I put some foam insulating material on the pipe coming from the pump. Finally, I added about 2' of hose to make a "loop" between the pump and the pipe to help keep the vibration out of the pipe and that has made for a very quiet pump..
Almost too quiet.... A couple of times, I didn't get all the air out of the system and had the pump on and it just ran and ran for who knows how long before I caught it and opened up a faucet.... Oh, it's still the original pump from 2002, so running it 'dry' does not really kill it on the spot.. :)
Anyway, lots of other posts on this too..
Good luck!
Mitch