Non Potable water ? In what respect is it not drinkable ? In my experience over the years with swimming pools , many people get sick from pools filled with good water that have not been filtered/clorinated correctly . I personaly used a diamatatious earth filtering system that removed most bacteria and clorinated minimally over night , never had a problem . This was the system used many years ago in Great Britain in public swimming pools when water , at least in Bristol , was of far better quality than comes out of most of the worlds taps today . Purified tap water came in many bottled waters in North America until finally goverments stepped in to change that , because it was not neccessarily safe , even much touted Spring water is not safe to drink because of the use of pesticides etc over a wide span of years . When you swim , you often swallow so i humbly suggest you have the 'None potable ' water tested before venturing to use it in your pool , with a title like that ,it could contain all kinds of hazardous contamination , tap water is safer and you do not get expensive hospital bills . I say that with tongue in cheek , because some years back a small town in Canada had e-coli in its drinking water , several people died , all due to the incompetance of the staff in charge of the purification plant . Just my slant on the subject . Colin