[swalling]

The map that they produced is very easy to unintentionally misread. The map shows the predicted contamination of groundwater locations based on the models. It does not show the locations where the actual tap water source is predicted or known to be contaminated.

For example, many large cities (San Francisco, Seattle, Portland) either do not use groundwater sources from within city limits, or only use it as a secondary source. Unless you use a private well, this map is therefore not super useful for understanding whether PFAS contamination of tap water should be a concern for you. The map likewise doesn't take into account water treatment or filtering.

[animal_spirits]

If you want to see the contaminants in your tapwater you can use the Environmental Working Group's tap water database here: https://www.ewg.org/tapwater/

[hammock]

Tap water is one thing. Agricultural contamination is quite another, and also is worthy of exploration.

Specifically water for irrigation, and processed sewage/sludge for fertilizer

[linotype]

> processed sewage/sludge for fertilizer

This one scares me the most, including whatever drugs people flush down the toilet that they pass

[theandrewbailey]

It's a population density map, just as XKCD pointed out: https://xkcd.com/1138/