2015 Water Smarts Calendar (free download!) is to get a water quality report from your utility to find the levels of allowed and measured contaminants in water leaving the treatment plant.
Extra credit: compare the quality of water from your tap to the utility's results. (Some utilities will test your tap water for free, or you can pay for a test kit or lab test.)
Aside: I met a guy from Hach that says they have a portable, fast water quality tester. It's too expensive for most households, but $4,000 is not too much for someone who wants to go into the business of inspecting tap water. At $50 per test, it pays for itself in only 80 tests. People are willing to pay for accuracy and speed.
After you read the report, feel free to tell me what you understood, what was confusing, and anything else. Just go here.