> It’s in the entire water supply Not quite. In the US about 15% of the population get their drinking water from private wells. I wonder if anyone has compared

> It’s in the entire water supply Not quite. In the US about 15% of the population get their drinking water from private wells. I wonder if anyone has compared groups that are similar except for whether they are on a well or municipal? It shouldn’t be hard to find such groups by looking at the boundaries of municipal water systems. For example on my street everyone east of me is on city water and everyone else is on wells. Both groups are demographically very similar.