Uhm, well here there is 1000 times more water that is been wasted directly to the ocean every second than the water that get used in the city, after all water is in extreme abundance in this region, so mostly this kind of issues affect dry or very poor regions of the world. Hell even in the super dry desert side of Patagonia they manage to get water without so much of a hassle so i will be damned if they cannot get water in buenos aires one of the places in Argentina that has the most abundant source of water. Going back to this kind of problem in the world, i think technology will solve this issue not so long from now, with graphene filters more likely or some other technological advancement that will make dirty cheap to just filter salty water or contaminated water directly in your tap without risk or need of any kind of chemical, still is still not available this technology but im pretty confident that it will be not to long from this moment.