The electrician who built your house probably took that line from the third prong on all outlets, and hooked it up to a water pipe. You can skip the prong and hook your strap to a water pipe if you want. That\'s probably not convenient though.
As the article said, the metal shell from most appliances that have a three prong plug is already wired directly to the third prong, so you can clip your wrist strap to a metal part on a plugged in appliance, and that will do the same thing. Or if you\'re worried about it, unplug the appliance and wind some wire around the third prong, then connect the wrist strap to the wire. EASY