Reports

Original analysis of the public record on private wells, computed from the same data as every county and town page and free to cite with a link.

• Arsenic in private wells: what homeowner tests show, state by state

  Nine state programs, hundreds of thousands of homeowner tests, and the federal record for everyone else.

• Nitrate in private wells: where it runs highest, and whether it is getting better

  Decades of samples, state by state and decade by decade. In most states the share over the limit has not moved.

• PFAS in private wells: what testing near known sources and routine testing each found

  Why the headlines and the odds for an ordinary well are so far apart, with the numbers from both kinds of testing.