As others have indicated, ...
Published by Norris Johnston, Owner and Principle Consultant at Water Wizard Consulting, LLC
As others have indicated, drift and system leaks often go unmeasured but function as blowdown. Remember, use of TDS and/or other tests must take into account outside influences (such as process leaks adding TDS or treatment chemicals adding TDS, etc). If treatment is added (such as phosphate) you might be able to test for this compound in various sewers to isolate any leaks to a specific area in the facility.