When you have a high ...

 When you have a high concentration of chlorinated hydrocarbons the chlorine becomes less effective. ( may be pesticide spraying time for crops etc. ).   Resolution = Stop using caustic chlorine  to reduce TDS.  Use instead RNA Archaea microbes that have the genetic code to reduce all TDS to their elemental/nutritional form.   When this process is completed there is no reason to dump into rivers etc.  Long term vigorous testing will allow the water to be recycled as potable.  Not economical to refit old stations. But the newer ones can start with the 100% recycling of their water.  No more drought complaints.