Loooking in 99 book 250.130(c) " Any accesible point on the grounding electrode system as described in 250-50" There is a note in the handbook stating that an interior metal water pipe more than five feet from entrance is no longer allowed due to the use of plastic piping and fitings. I went to a service call where the person was belted when he got into the shower. Turns out a kitchen receptacle was grounded to a cast iron sewer pipe that went to a septic system. Not a good ground I guess. The receptacle somehow was fried and the cast iron pipe became live. Turn on the shower, water going down the drain, feet in water, grab the faucet, ZAP! He was ok, and his kids were next in line to take a bath. Fortunately he went first. Also the drain on the sink was so hot that the water in the trap was actually boiling and making steam. I havent seen anything like it before or since.