[TowerTalk] station grounding question

[Gary Slagel]

I put my shack together several years ago and today was reviewing my grounding system hoping that I could find a magic trick that might quiet some of my noise on 80 and 160.
I've got a decent grounding bus on the back of my desk with a #6 copper wire running about 8' through the floor to the electrical grounding wire that runs from the electrical panel about 6' outside to ground rods.  I could also or instead run my grounding wire to a copper cold water pipe that runs about 75' before it leaves the house.
Am I better off leaving it as is, grounded to the electrical ground?  Or would the cold water pipe be better?  
Gary KT0A