Please tell us more.
Reuse water varies widely in how safe it is.
In the US reuse water is usually safe around people, but obviously not for consumption. Have seen some unlicense stuff, real bad, scary.
Overseas reuse water can be nothing more than perfumed crap water, in fact, in many countries I have worked in that is all you will ever see, no secondary treatment at all.
Most use obviously is for irrigation.
Have seen just a slight bit of use for supplying hose bibs that are in restricted areas and well marked, but this would be rare.
I could easily see it being used for flushing toilets, but have never seen it done before, except overseas.
What are you looking at, I am interested.
PUMPDESIGNER