I don't know, the machine has a picture of all the filters "used" and there are lots of visable tubeing and what apears to be an ro unit if you look thru the plexi above where the water is dispensed.

On a side note: This is a matter of what is right and what is wrong I will do everything within the limits of the law to make this store pay. If I do not get what is fair not only do I plan to sue but I will file for peaceful protest permits and stand in front of their parking lot with signs stateing that they are selling contaminiated water. It is contaminated with copper but if people choose not to stop and talk to me they may asume it is contaminated with other things. Hey I cant control what other people think. I think a sign saying "Walmarts sells contaminated water that killed my pets" would be quite effective.