NEC 250.50 says a service panel should be grounded to a metal/copper water pipe. In my case, PEX was installed between the water meter and house. Four inches of copper pipe is exposed on both sides of the foundation wall. PEX is used in the house. Am I getting a sufficient ground for the service panel since this copper pipe is isolated in the wall? I do have a 8’ ground rod connected to the service panel too, but ground is really soft. Thanks.