The Water Dept., are going to be replacing the metal pipes in our village with plastic and state that anyone using the mains for an earth will have to change. My house was built in 1966 and has a copper supply pipe. I see that there is a wire from my electrical consumer unit securely clamped to the sheath of the incoming electric cable so am I correct in assuming that the house is adequately earthed? All internal water pipes and fittings are properly bonded. Thank you.