What Is a Performance Data Sheet on a Water Filter?

If you want to know what a filter actually does, the box is the least reliable place to look. The performance data sheet is better: it’s the document behind the certification mark, and certified filters come with one.

What’s on a performance data sheet?

The EPA’s guide to lead-reducing filters says claims that aren’t printed on the packaging, such as lead reduction to 5 ppb or less and Class I particulate reduction, can typically be found on the data sheet inside the filter packaging, in the certifier’s online listing or on the maker’s website.

A typical sheet, like the one PUR publishes for its pitcher filters, lists:

• the pitcher and filter model numbers it applies to;
• each substance, grouped by standard (NSF/ANSI 42 for taste and odor, 53 for health contaminants, 401 for emerging compounds), with the percent reduction measured in testing;
• the rated capacity in gallons, the service flow and the water temperatures it can be used with.

PUR’s sheet also shows why the model number matters: for the same pitchers, its PUR PLUS filter is listed for lead and Total PFAS, and its basic filter is marked “Not Certified” for both.

Is a data sheet the same as a certification?

No. The maker writes and publishes the data sheet, and some sheets mix certified results with results the maker calls “independently tested” or doesn’t explain at all. A high percentage on a sheet isn’t a certification on its own.

Use the sheet to find the model numbers and the claims you care about, then confirm each one in the certifier’s listing (NSF, WQA, IAPMO and others). In our pitcher comparison, several makers advertised far more than their listings showed. Past the rated capacity, the results on the sheet no longer apply, so replace the cartridge on time.