DoD acknowledged in a March briefing to the House Armed Services Committee, that water is contaminated with suspected carcinogens on at least 126 US military reservations. The $44,000 report (link below) is specific to the contaminants Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA). Many reports place the number of bases, open or decommissioned, with contaminated water or sites at 400 or more.
Military Times Story:
https://www.militarytimes.com/news/your-military/2018/04/26/dod-126-bases-report-water-contaminants-harmful-to-infant-development-tied-to-cancers/
Link to the briefing entitled: Addressing Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA):
https://partner-mco-archive.s3.amazonaws.com/client_files/1524589484.pdf