How deep must a metal water pipe be in contact with the earth to serve as a grounding electrode?

A metal water pipe must be in contact with the earth for a minimum depth of 10 feet to serve as a grounding electrode. This requirement is specified to ensure that the grounding system is effectively connected to the earth, which is critical for safety by providing a path for electrical faults to dissipate. When the water pipe reaches this depth, it typically ensures good conductivity with the earth and protects electrical systems from surges or faults. This depth is based on widely accepted electrical codes that prioritize safety and reliability in grounding systems. The other specified depths do not meet the minimum requirement for effective grounding as defined by electrical standards.