Australia - Highest percentage of recycled water

SOUTHEAST Queensland could have the highest percentage of recycled water in its drinking supply of any place in the world if the drought continues.If Brisbane's dams are almost empty when the recycled water pipeline comes on line late next year, all that would be left in the dam would be a 50-50 mix of desalinated and recycled water.
The chairman of the Water Commission's recycled water advisory panel, University of Queensland professor Paul Greenfield, said he wasn't aware of a higher recycled water concentration anywhere.

Video on water treatment as well as news from Australia I found interesting.