Desalination plants, or desalination chambers, were machines constructed to the bottom of some of Tipoca City's domes with the purpose of desalination—the act of removing salt from ocean water—in order for it to become distilled water usable in the city. These plants were fitted with compressor units as well as tanks for condensation and evaporation. Water was pumped from the ocean via city support pylons into tanks of untreated water.
With funding from the Republic from before the time of Palpatine a permanent camp had been established at Alpinn's archeological station which included prefab dwellings, wind turbines and a desalinization plant.
In Catalyst: A Rogue One Novel, desalination is misspelled with an extra z.