Hi @stevie - Jumping in here (first-time posting actually :)
You find anything else on this? I'd be interested in learning along with you.
Some reactions / questions:
-- It looks like most of the feedback you got from twitter was more about the techs/platforms. In terms of getting the data...
-- Are you looking at private or gov't data? Private could be a company like mytapscore.com or a lab like awslab.com which does the actual testing (mytapscore just packages things). People go to these when they're gov't doesn't offer tests and/or if they're offered but it'd take long / involves beaucracy, etc. If gov't data, I imagine there's variance by state. In CA, local water utilities offer tests and they report certain things up to the state. Not sure exactly what that looks like (yet).
-- Data ownership and privacy issues are involved here... I'm not sure it's clear to anyone whose "data" well water testing belongs to. By default, I think it belongs to the home owner. (My parallel is in the still developing world of healthcare: a test on whether or not you have cancer is first and foremost yours and hospital can't just share that with people without your consent.) The reason this matters: Home / property values go down with bad results; and there are privacy + stigma concerns to consider if you can ID an individual who has, say, lead poisoning. --> So stuff that is released is aggregated enough to not be identifiable. But not everyone releases data. And I think there are different data types / standards among those that do.
-- I'd love to learn more about the Wisconsin zip-code level data you mentioned. Can you share a link?
-- Have you poked around data.gov? https://catalog.data.gov/dataset?q=well+water&sort=score+desc%2C+name+asc&as_sfid=AAAAAAXHiPQ9FtwN-0HoqrEvwh6kl3bWSUVc4ax6nXqURsqKvBjkiMqz9j9N4MZW1D7t3Ts0VQG2msUtfAmiv4beWX8Y_dNnq6niC9w4oCHAvOTatW1vZzGB8mLl-kHRvYJblk4%3D&as_fid=a02557aeae533d07a105850dfc1b6b37b0b757fd
-- Also possibly relevant: http://waterchallenge.data.ca.gov/Data/index.html