"Removes 99% of contaminants" is a marketing sentence, not a guarantee. A filter removes only what it's certified against. This page is the whole decision on one screen: the NSF decoder, how to read your own water, and why the cartridges, not the device, are the real cost.
Read your own water first, find your one real problem, buy the cheapest filter certified for that specific problem, and budget the cartridges. Don't buy the filter whose ad scared you most.
"Removes 99% of contaminants" with no standard named is marketing. The NSF/ANSI number is everything. A filter certified for chlorine taste is not protecting you from lead, no matter how the box reads.
| Standard | What it actually covers |
|---|---|
| NSF/ANSI 42 | Chlorine, taste & odor: a flavor upgrade, not a safety one |
| NSF/ANSI 53 | Lead and health-related contaminants |
| NSF/ANSI 401 | Emerging contaminants / some pharmaceuticals |
| NSF/ANSI 58 | Reverse osmosis (broad removal, including many dissolved solids) |
For PFAS specifically, look for a filter that names PFOA/PFOS reduction in its certification. It's increasingly listed under 53/58 testing.
Your utility's annual Consumer Confidence Report and the EWG tap-water database tell you what's actually in your tap. Most US municipal water already meets safety standards, so the real question is which specific thing you want gone, not "all contaminants." That one answer picks your filter for you.
A $35 pitcher with $8 filters every two months runs ~$50/yr in cartridges, more than the pitcher, every single year. Price the refills, not the sticker. Over five years the cartridge bill, not the unit, is your real cost.
Taste only → pitcher or faucet filter ($30–$40). Lead or PFAS → a filter certified for it (wide-range pitcher or under-sink). Well water or a serious problem → reverse osmosis (removes nearly everything, but wastes water, runs slow, and strips minerals; overkill for most municipal water).
A genuine necessity for lead service lines, PFAS hot-spots, private wells, and immunocompromised households: a taste upgrade for everyone else. The universal urgency in the ads usually isn't real. Buy for your water, not the scariest commercial.
The NSF decoder plus the don't-get-played checklist, so you can pull it up in the store aisle. One email, no spam.