Metal water piping systems must be bonded to which of the following?

Metal water piping systems must be bonded to ensure electrical safety and prevent potential electrical hazards. Bonding helps in establishing a low-resistance path to ground for electrical faults, which can prevent hazardous voltage levels on non-current carrying metal parts.

Bonding metal water piping systems with the building foundation is crucial because it can help dissipate electrical surges or faults safely. Additionally, bonding them to nonmetallic pipes ensures that there is a continuous path for electrical grounding, as PVC or similar materials can also have metal fittings that need to be grounded. Furthermore, connecting to an earth grounding rod provides a low-resistance path directly to the ground, further enhancing safety by ensuring that any fault current is directed away from the building structure.

In this context, the option indicating any of these is correct because bonding can involve any or all of these components: the building foundation, nonmetallic pipes where applicable, and the earth grounding rod. This comprehensive approach to bonding enhances overall safety and compliance with electrical codes.