I wonder if the water pumps or running water makes any sound or vibration?
I wonder what your power plugs look like, 2 or 3 flat pins, round pins , or 3 squarish pins?
How are the lights fed, are the wires in a metal conduit, plastic conduit, or twin and earth in no conduit?
Is your water feed pipe metal or plastic?
How far are you from the nearest power company earth (either sub or mini sub, or 11kV-240V pole mounted transformer with a proper earth)
Do you have an electric railway line nearby?
Are all the light switches in the live line and not the neutral line?
Safety yes, but sleep problems? I think that if that were a cause of sleep problems, half the world would not sleep.
Good to get your house up to standard though