This answer indicates that the water pipes should bonded to the electrical ground even if a grounding rod is used. How would one normally tell if that is the case? Is that bonding required to be accessible, or can it be hidden behind walls or buried? Where in the water system would it normally be bonded (e.g., before the main water shutoff, after, at the hot water tank)?
I recently had my electrical panel relocated and replaced, and don't recall seeing anything running from the panel to a water pipe – in the old panel or new. The electrician put in an intersystem bonding bridge, so the new ground rod, ground from the panel, and ground from the cable service are connected to it. I suppose that's where the bond from the water pipe would go?
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My cold water piping is bonded to the panel at the cold supply of the clothes washer. The hot piping is presumably electrically connected to the cold through the brass mixing valves of the shower and tub. There is negligible resistance between the cold and hot pipes at the washer supply valves.
Following Tyson's link I see my kitchen and lavatory faucets are not bonded because they are connected with non-conducting flexible supply lines; an ohmmeter test confirms this. I tested this by plugging an extension cord into an outlet and measuring the resistance between the ground of the cord and the point under test.