we have been using this system for several years, previously we were using a Brita, thinking that was good enough, well we were wrong! once we tried Zero we realized how much better the taste and the purity are using the Zero filters. when we live in Florida we needed to change the filters in one month, now that we are living in Santa Fe NM we are changing the filters every three months, it is great that Zero provides a meter to let us know when the filter needs to be changed. I recommend Zero and it is  much better than bottled water and better for our environment