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NSF 42 vs 53 vs 58 — Water Filter Certifications Explained
Not all NSF certifications are equal. Here’s what each one actually means — and why it matters when buying a water filter.
NSF 42 covers only taste and odor. To remove PFAS or lead you need NSF 53 or NSF 58. Most cheap pitcher filters are NSF 42 only — including standard Brita.
Quick comparison
NSF 42 — Taste and odor only
NSF 42 is the most basic certification. It covers aesthetic effects — chlorine taste, odor, and particulates. Most standard Brita pitchers are NSF 42 certified.
NSF 42 does NOT cover PFAS, lead, fluoride, heavy metals, or any health-related contaminants. If a filter is marketed as “removes 99% of contaminants” but only has NSF 42 — that claim refers to chlorine taste, not dangerous chemicals.
NSF 53 — Health contaminants
NSF 53 covers health-related contaminants including PFAS (PFOA, PFOS), lead, VOCs, and over 50 other chemicals. This is the minimum certification you need if you’re concerned about PFAS or lead.
Filters certified to NSF 53 include activated carbon and catalytic carbon systems. SpringWell CF+ and Aquasana Rhino are both NSF 53 certified.
NSF 58 — Reverse osmosis
NSF 58 applies specifically to reverse osmosis systems. It covers everything NSF 53 does plus fluoride and arsenic removal. If you want the most comprehensive filtration, an NSF 58 certified RO system is the gold standard.
APEC ROES-50 is NSF 58 certified and removes 99%+ of PFAS, lead, fluoride, arsenic, and 1000+ other contaminants.
NSF 401 — Emerging contaminants
NSF 401 covers emerging contaminants like pharmaceuticals, pesticides, and herbicides. It’s a newer standard and fewer filters carry this certification. It does not cover PFAS or lead specifically.
How to verify NSF certification
Don’t trust marketing claims. Verify any filter yourself at the official NSF International database at nsf.org/certified-products. Search by brand name or model number to see exactly which contaminants are certified for removal.
We check every filter on this site against this database monthly. If a certification has expired or been revoked, we update our ratings immediately.