Absolutely SILENT Jazz Bass with NO mods

[guidold]

Hi, I'm new to this forum, I thought I just HAD to register so I could share something strange that has happened to me and still very much puzzles me.
I have a CIJ Fender Jazz Bass '62 Reissue, which, like a typical jazz bass, has single coil hum, especially when you favor one of the pickups.
The thing is that I had some major humming problems in a particular room of my house. I later found out that the humming problems were due to the fact that the power outlets of that room were actually not connected to ground. I knew that if I connected the outlets to ground, my humming would be reduced to the normal levels of single coil pups.
So, I connected the ground cable of the outlet to a metal water pipe that I have in a bathroom on an adjacent room, presuming that it would serve as a good ground.
I turned on my amp, and...magic (well, at least to me it seems like magic): no hum whatsoever, whatever the pickup and tone knob combination. NONE. You can barely notice it when the amp is on at full blast volume.
I also plugged in a Fender Classic 50s Telecaster which also has single coils, and NO hum, nothing.
So, could all single coil noise problems be solved just by really good grounding of the electrical circuit of your house? I know this isn't your typical scenario of grounding, as the ground in houses is almost never so close to the power outlets. I'm just guessing, I know almost nothing about electricity.
If I have time I will post a video to show that I'm not bluffing, and that my Jazz Bass is absolutely silent.

Greetz to all!