I would just reprocess waste water, maybe they do it. A waste treatment plant can produce potable water at some additional expense (tertiary).
I know they lose a lot to evaporation and leakage.
They do some, for irrigation, and more recently (10 years or so), they use reclaimed water for flushing toilets. Adds a lot to the construction costs (double the pipe/install), but there is not much of a choice to be made out there.
And yes, there are losses.
One of my friends lived in this development until he moved to Palm Beach Gardens. Lots and lots of loss potential in that pond. There are thousands more like it out there.
My MIL lives here:
