A new report from Circle of Blue's report on PFAS in drinking water, dated October 23, 2026, raises a question every homeowner with a filter should be asking. Its summary opens with a point about results: "When PFAS concentrations in drinking water fall below laboratory reporting limits" the number on a page can hide how much is really there. You do not need a chemistry degree to act on that idea. You need to know exactly what your filter has been tested to remove, and how that list compares with what your own water report says.
A Certification Is a List, Not a Promise
A filter badge is a claim about specific contaminants, tested under a specific standard. The certification sheet lists which contaminants the unit was tested to reduce, the starting concentration used in those tests, and the rated capacity. PFOA and PFOS are the two PFAS compounds you will most often see named on these sheets, but a product only covers them if the sheet says so. A carbon pitcher certified for chlorine taste and odor is a different product from one certified for lead or PFAS reduction, even when both carry a similar logo.
Read the Sheet in Four Passes
Start with the certifying body and the standard number, then confirm the exact contaminant names listed. Next, read each reduction claim closely. A sheet may say a unit reduces a contaminant to a stated level from a tested starting concentration. Those test conditions matter, because your water may sit above or below the level used in testing. Third, check the rated life, usually given in gallons or months, and put the replacement date on your calendar. Fourth, confirm that the model number on the sheet matches the cartridge you plan to buy, since similar product names can carry different certifications.
Ask the seller to show you the sheet itself, not just the product page. Marketing pages sometimes display a logo without naming the contaminant, and that gap is worth noticing before you pay for anything.
Start From Your Own Result
Your water test is the other half of the match. Look past the headline result and find the reporting limit for each contaminant on your report. The limit tells you how sensitive the test was on that day. If your reporting limit sits above the level a filter is certified to reduce, the report cannot confirm or rule out the need for that filter. In that situation, a more sensitive test will tell you more than a stronger filter will, because it tells you what you are actually dealing with.
Write the contaminant, the result, the reporting limit, and the test date in one place. When you compare that line with a certification sheet, you can see at a glance whether the filter addresses the thing your report measured.
Questions to Ask Before You Buy
Bring these questions to a dealer, installer, or manufacturer's support line. Which contaminants does this exact model certify for, and under which standard? What were the test conditions for each claim? How often do the cartridges need replacing, and what does a year of replacements cost? Does the warranty cover how well the filter performs, or only the housing? Clear answers to these questions tell you more than a logo does, and vague answers are a reason to keep shopping.
Health Questions Go to the Right People
A certification sheet can tell you what a product was tested to do. It cannot tell you what a measured level means for the people in your household. For questions about exposure or symptoms, contact your doctor or your local health department. Keep your water report with its date so they can see what was measured and when.
The goal is a match. The filter's tested list, your test's reporting limits, and your own priorities should point to the same contaminants. When they line up, the badge means something. When they do not, the badge is just a logo on a box.