While desalination requires disposing of all the waterborne particulate, the water can sometimes be precious enough that we bear it. I heard a radio report yesterday [0] about how investing in desalination helped mitigate USA CA Catalina Island's direly depleted resivoir. That's not to say that brine treatment or disposal isn't costly, more that - so long as people are committed to living in dry areas and can afford to, they will pressure their local governments to keep the area habitable.

[0] https://www.marketplace.org/2022/07/18/drought-technology-po...