I've lost track of the exact year; however, ZeroWater has been a welcome member of my household for many, many years.  Way back when the filters were at least 4x  bulkier than the ones I'm using  now.   At the time I challenged the companies pledge of zero impurities.  When their tester registered zero, i was not a believer.  I purchased another tester and got the same reading.   Well  i could not  understand the process but i understood the best water I've ever  tasted.  I was so young  then and today,  I must admit time has created a huge difference between ZeroWater then and now.  They kept their promise of zero water but despite my efforts that water couldn't keep medicare and aarp away.   Zero Water  . . . . The Best I've ever Tasted.