I’m sorry but I don’t use tap water for any of my animals or drink it myself. If $5 for a pack of waters that lasts forever is to much then I shouldn’t be keeping animals. They put all kinds of stuff in tap water, I’ve tesed the water thousands of times as I worked for a custom fish store, and I’ve seen some crazy levels that made me not want to drink it. So my animals and I drink bottle water. I have those big hot/cold 5 gallon water dispensing machine. So it’s really convenient.