I used my water kit in my old 32bit system for over 3 years without a problem.
I now run a 64bit socket 754 so i have had to "adapt" my cpu water block mountings. As soon as i have the reservoir built I will be fitting my water kit.
I did once have a major water spillage inside my 32bit pc during the early stages of fitting, but I left it to dry out, checked it all, and had no problems at all.
Electronics generally has no problem with water, its the impurities in the water that causes the problems.