In the not too distant future, water at our taps, we are told, will be a luxury, not a utility, in many countries.
So, there will be a high demand for devices and systems which make a little water go a long way.
Considering apartments only, nearly all the water we use is for keeping ourselves
and our pets clean, so that’s a prime area for gadgetry.
So I looked around at water-saving devices already in use, ruling out massive and costly grey-water re-use systems and composting closets.
My built-in random generator flicked up a common form of carpet [rug] cleaner as a starting point
These portable machines typically first blow detergent/steam/moisture into the carpet and after a scrubbing phase, suck most of the wetness back into storage.
To conclude this meandering I visualise a miniaturised version of this machine adapted to clean animals and people as if they are carpets, i.e. with no splash, spill, and minimum water-use, and therefore, waste.
As usual, the devil’s in the details even if the principle is feasible.
The Devil might like a powered fang-brush with a blow-suck supply of his favourite battery acid for example.