Jimmy wrote:
"Using a cold water pipe is a bad idea and is not allowed by some local
codes even though it may be allowed by the national code."

You don`t want to be electrocuted when holding an electric appliance and
a cold water valve simultaneously.

My electric company, the former Houston Lighting and Power Company,
writes:
"All services shall be properly grounded. Note - NEC requires grounding
to a "metallic underground water piping system" if available. Acceptable
alternatives include a driven ground rod which is preferred by HL&P Co.
regardless of the type grounding electrode used. NEC requires that the
"interior cold water pipimg system" be bonded to it."

Best regards, Richard Harrison, KB5WZI