Product review (5 stars): Excellent filter for NSF 42 standard.
Some reviews complain that this filter is not NSF 53 rated (which removes cysts and other micro organisms). Like most filters of this style, it's rated NSF 42 for taste, odor and esthetics. If you NEED a filter better than NSF 42, you've got more problems with your municipal water supply than can be addressed with a simple refrigerator filter.