Depends on many factors but brackish groudwater does exist near coastlines either naturally or via intrusion from human over pumping. Example of the latter fro

Depends on many factors but brackish groudwater does exist near coastlines either naturally or via intrusion from human over pumping. Example of the latter from LA: https://www.wrd.org/content/regional-brackish-water-reclamation-program https://www.wrd.org/content/regional-brackish-water-reclamat...