It would certainly make sense to require all new houses to have a dual water supply - fresh for drinking and grey for most other purposes. Some countries run a dual water supply system for this reason, but it would be impractical to fit that to old houses. New houses, though, that's perfectly possible. Collected rainwater, recycled water from showers etc, why not?

I have referred to an arena I saw in Delos, I believe, built by the Ancient Greeks. While it looked at first sight like any other stone-built arena there were slight slopes on the seats, a slight incline on the rows of seats and so on, so that when it did rain it was a giant funnel, routing all the water to underground storage.

When people actually perceive water as important, much can be done. But the most detrimental is to set up companies whose main remit is deliver profits to shareholders where water is just the medium to do that.