We have been using Zerowater for years.  We love it and recommend it to everyone.  We have a standing water dispenser that we bought from a scratch and dent sale that we were using for 5 gallon bottles.  We bought the system for Zerowater and use it now.  We just add tap water to the large tank and we have great filtered water.  It out-tests and water from any company, bottled or tap.  Any brand you try, Zerowater wins every time!  Highly recommend this from experience of using it for years. So save yourself the trouble of those heavy 5 gallon jugs and cases of bottled water.  Make your own pure water!