Bill,
Here in NJ the state makes me do a visual inspection every year that a community pool opens up. It is a non effasive type of an inspection. I look for loose wires, connections, new equip., no loose bonded equip., and test GFCI's. If something doesn't look good, then I can require another "Bonding" inspection. This bonding inspection happens to all public pools in NJ. The get tested every 5 years. A contractor would come in to this pool, and test resistence between all points. He has to be satisfied that it is below a safe potential. The makers of pool and pool equipment also make the meters that are used for this test. If you want info about the test, let me know.
Harold