There are two possible answers. The water pipe coming into your house, as long as it stays metal, will be unchanged in what it does as the Grounding Electrode (250.52).
Part two: any equipment grounds for fixtures or outlets that were connected to the interior water pipe (back when it was allowed) will now have to be rerouted to the electrical system EGC. The remaining metal pipe that you don't replace will need to be bonded according to 250.104.
