This distiller is a highly functional and economical machine. It produces a considerable quantity of clean water in a safe manner. I have two complaints: (1) the machine takes about six hours to heat and distill water. I've found that using pre-boiled water saves quite a bit of time (and probably money); (2) the machine is equipped to turn itself off once no water remains. Unfortunately, this leaves a nasty mineral residue in the machine's basin. I recommend turning the machine off once it is near completion. This will help delay and minimize the buildup of deposits in the basin.