Are your above ground water tanks & below ground cistern tanks FDA approved and is it safe to store water in these tanks? Posted on April 21, 2016 by Mark Peabody Yes, it is safe to store water in Peabody’s above ground water tanks and below ground cistern tanks shown on our website. The resin used to manufacture these tanks meets FDA specifications for safe storage of potable water. Mark Peabody What is the difference between a septic and a cistern tank? Are your above ground tanks & below ground cistern tanks NSF approved?