There is a critical need for drinking water, across the globe. That can only be remedied “as best we can” by developing techniques to remove salt from saltwater. Among the most simple of these is: To create a pond, for pumping saltwater into it/ then covering and sealing that pond with a black plastic sheeting. In HOT climates the sun then evaporates the water, separating it from the salt, and you can or will bleed that water vapor off from under the plastic with a small hose, and a potential solar operated fan to blow the hot moisture laden air from the top of the pond into a cooling cycle, so the water does condense where you want it. The obvious choice for a cooling medium is the ocean from whence the saltwater was taken. So a pipe line is run into the ocean where the water vapor is condensed into a liquid inside the pipe, and then contained into a separate tank for use. To keep the system going, it is probable that a trench will be cut into the shore so the water level of condensed drinking water is allowed to flow by gravity to a sump situation from which it is then pumped by a second mechanism into a holding tank. Or the drinking water holding tank itself, is simply located here below the surface so as to keep it cool. Refill the pond only at night or early morning so as not to lose an heating or evaporation by the sun. To aid in evaporation, a heating circuit can be developed and circulated within the pond. Several methods are simple.
The people who create solar salt, by simply evaporating water into air/ can tell you how to build a pond and how much water you can gain over time. Every little bit will soon matter.
In addition to creating drinking water, the need for direct irrigation is massive, and must be done correctly from this point forward. That would be in an orchard for instance, a water line that does not leak, other than through specific pipes driven below the surface to actually feed the roots only, every thing else is allowed to die. That would be in high value agriculture, a pipe that is laid just below the ground surface, with small cuts in the pipe which then leak out to feed the plants on each side. A simple tractor driven trenching tool, will easily bury the plastic piping: that tool can contain an insertion device that cuts the pipe at measured intervals. Buried close to the surface to avoid evaporation, through the use of dirt; the piping can be pulled back out of the ground for reuse/ or left season to season. NOTHING gets irrigated that is not obviously and truly necessary or critical to life. Such things as lawns are irrelevant; such things as golf courses if in high demand; are allowed a small ration, to retain what they believe is absolutely critical to sustain business; like it or not.
There will be a measured amount per individual living on a property; that is fair to all. Any excess, will be charged as a percentage of income; to establish the price shall not punish the poor alone.