Some places like BKK have little worry about water as it is among the most effluent resources and the water bill among the cheapest. Human as a whole however faces water shortage pretty soon as in China it probably emerges earlier than anyone else. The solution has to depend on recycle and reuse because water shortage is not a natural problem but human problem. It has to be solved by human.
The very idea of consuming reprocessed human, animal and industrial waste can turn people’s stomachs. But it happens more than most realise. Even municipalities that do not pump waste-water back into aquifers or reservoirs, often draw their drinking supply from rivers that contain the treated effluent from communities upstream.