If you've looked at tap water quality reports lately, something stands out: PFAS are showing up in places they shouldn't be. The EPA found PFAS in at least 2,854 water systems across the US. In April 2024, the EPA set its first-ever federal limits on PFAS in drinking water. What scientists have known for years is finally getting regulatory attention: these chemicals are everywhere, they don't break down, and they're worth filtering out.
Here's the catch: not all water filters are equal. Some remove chlorine but miss PFAS entirely. Others tackle lead but leave chloramines behind. The marketing is confusing on purpose — brands claim to "reduce" PFAS without actually verifying the numbers. If you're shopping for a filter, you need to know what you're actually filtering for and which certifications mean something.
What's actually in tap water (and what matters)
PFAS: the "forever chemicals"
PFAS are synthetic chemicals in nonstick cookware, food packaging, stain-resistant fabrics, and firefighting foam. They're called "forever chemicals" because they don't break down in the environment or your body. The EPA set health advisories at near-zero levels: 0.004 parts per trillion (ppt) for PFOA and 0.02 ppt for PFOS.1
PFAS exposure is associated with changes in liver enzymes, thyroid function, and reproductive hormone levels. The science is still evolving, but the EPA decided the evidence was strong enough to set national drinking water limits. Here's what matters for your filter: most cheap activated carbon filters don't touch PFAS. If you want PFAS removal, you need NSF 58 certified reverse osmosis or NSF 58 certified advanced carbon.
Lead: the silent neurotoxin
Lead pipes are still in about 6–10 million US homes, mostly built before 1986. Lead leaches into water especially in older systems or when water pressure drops. The EPA's action level is 15 ppb — but there's a problem: no amount of lead is actually safe. Even low levels hurt kids' brain development.2 Most activated carbon filters don't stop lead. Reverse osmosis and ion exchange systems do.
Chlorine and chloramines
Chlorine is added to kill bacteria — it's necessary. But too much leaves a chemical taste and smell. Research suggests long-term chlorine and chloramine exposure may increase cancer risk in some groups. [inference: studies on disinfection byproducts] NSF 42 certified filters (the cheap ones) remove chlorine and odor. For most people, this is fine.
Microplastics: the emerging question
Microplastics show up in tap water around the world. We still don't know the health effects, but reverse osmosis removes them. Activated carbon does not.
How water filtration actually works
Activated carbon (cheap, but limited)
Activated carbon traps chemicals through adsorption. It's the most common and affordable filter technology. It removes chlorine and taste/odor well, and some pesticides and VOCs. But it doesn't remove dissolved minerals, PFAS (unless specifically NSF 58 certified — rare), lead, or microplastics.
Cost: $20–$80 for pitchers; $100–$300 countertop. Lasts: 2–6 months for pitchers, 6–12 months countertop.
Reverse osmosis (thorough, removes PFAS)
Reverse osmosis forces water through a semi-permeable membrane (0.0001 microns), blocking almost all contaminants. This is the best filtration technology available for your home, and the only standard NSF certifies for PFAS removal (NSF 58). It removes PFAS (90%+ when NSF 58 certified), lead (often 95%+), chlorine, chloramines, microplastics, dissolved minerals, most pesticides and industrial chemicals.
It removes all minerals, leaving demineralized water — fine for most people, but some prefer a remineralization cartridge for taste. It's also slower (25–50 gallons per day for countertop systems) and wastes water (about 3 gallons per 1 gallon filtered).
Cost: $300–$800 countertop; $600–$2,000 under-sink installed. Lifespan: RO membrane 2–5 years.
The certification that matters: NSF
- NSF 58: The only certification that proves PFAS removal (90%+). If you want PFAS gone, this is the marker that matters.
- NSF 53: Health effects — removes lead and certain pesticides. Doesn't guarantee PFAS removal.
- NSF 42: Taste and odor only — removes chlorine. That's it.
Lots of filters claim to "reduce" PFAS without NSF 58 certification. They might reduce it somewhat, but NSF 58 is the only third-party standard that independently verifies 90%+ removal. If the label doesn't explicitly say NSF 58, the PFAS removal claim isn't independently verified.
Filter comparison: what to buy
Pitcher filters ($20–$80)
Remove chlorine and improve taste. Good for renters and tight budgets. Do not remove PFAS, lead, or microplastics. Convenient but seriously limited — if PFAS or lead is a concern, they won't help.
Countertop filters ($150–$800)
Sit on your counter, no installation required. RO models remove PFAS, lead, and microplastics. Good for renters who want serious filtration. Check for NSF 58 (PFAS) or NSF 53 (lead) certification on the specific model.
Under-sink filters ($600–$2,000)
Install under the sink. Usually reverse osmosis or multi-stage. Best for homeowners who want comprehensive filtration without losing counter space. All NSF 58 certified systems perform similarly — the differences are warranty, filter lifespan, and whether they include remineralization.
Whole-house filters ($2,000–$5,000+)
Most people don't need whole-house filtration. Your concern is drinking and cooking water. A good under-sink or countertop system handles that.
FAQ
Does my tap water actually have PFAS?
Check the EWG Tap Water Database or ask your water utility for a quality report. Most urban areas have detectable PFAS. Even if your test is clean, filtration makes sense if you're concerned — 2,854+ water systems have documented PFAS per EPA 2024 data.
Will a pitcher filter remove PFAS?
No. Standard pitchers (Brita, PUR) won't touch it. Some newer models claim PFAS reduction, but without NSF 58, those claims aren't verified. If you want PFAS gone, get NSF 58 reverse osmosis or NSF 58 certified advanced carbon.
Is RO water safe to drink every day?
Yes. It removes minerals, but you get minerals from food. No established health risk. Want minerals back? Add a remineralization cartridge ($50–$100).
Is Brita enough?
Brita (NSF 42) removes chlorine and taste. It does NOT remove PFAS, lead, or microplastics. If those matter, Brita won't work. If you just want better taste, it's fine.
The bottom line
Three things determine your choice: what bothers you (PFAS and lead require NSF 58; chlorine taste requires NSF 42), where you live (renters need countertop or pitcher; homeowners can invest in under-sink), and your budget (pitchers $20–$50; countertop RO $300–$800; under-sink $800–$2,000 installed). If PFAS or lead is a genuine concern — not vague health anxiety but actual contamination you've tested for — don't compromise on NSF 58. That certification is where the science backs up the marketing claims. Also see our related articles on PFAS in cosmetics and endocrine disruptors.