NSF/ANSI 53: Health-related contaminants
Official title: Drinking Water Treatment Units - Health Effects
Covers filters tested to reduce contaminants with health effects, such as lead, cysts, VOCs and PFOA/PFOS. A certified product holds only the claims on its listing, not every claim in the standard.
What it can cover
- Lead (listing claim: "Lead Reduction")
- Copper (listing claim: "Copper Reduction")
- Cysts such as Cryptosporidium (listing claim: "Cyst Reduction")
- PFOA and PFOS (listing claims: "PFOA Reduction" and "PFOS Reduction")
- A set of seven PFAS (listing claim: "Total PFAS Reduction")
- Trihalomethanes (listing claim: "Trihalomethanes (TTHM) Reduction")
- A group of VOCs that includes TTHM (listing claim: "VOC Reduction")
- Pentavalent arsenic at 50 ppb or less (listing claim: "Arsenic (Pentavalent)<=50 ppb Reduction")
- Chromium, mercury, cadmium and selenium
- Asbestos, radon, microcystin, MTBE and many single pesticides and solvents
What it does not
- Nitrate or nitrite. NSF lists that claim under NSF/ANSI 58.
- Fluoride. NSF lists that claim under NSF/ANSI 58.
- HFPO-DA (GenX). No NSF or WQA listing shows a claim for it.
- Haloacetic acids (HAA5) as a group
- Bacteria and viruses
- Lithium or uranium
The usual mistake
Reading "certified to NSF/ANSI 53" as "removes everything in 53." Certification is per claim. A filter certified to 53 only for cyst reduction has not been shown to reduce lead.
The fine print
- Always match the exact claim on the listing, not the standard number on the box.
- PFOA and PFOS claims moved into 53 from NSF Protocol P473.
- NSF says a PFAS claim requires reducing PFAS below 20 ppt.
- That is well above EPA's 4.0 ppt limits for PFOA and PFOS.
- EPA says current PFAS certifications do not yet show a filter reaches EPA's levels.
- Some NSF listings note a PFOA/PFOS claim was tested to the 2021 edition.
- NSF listing footnotes define Total PFAS as PFOA, PFOS, PFHxS, PFNA, PFHpA, PFBS and PFDA.
- NSF says work to align 53 with EPA's 2024 PFAS rule is still underway.
- The newest edition NSF has posted is NSF/ANSI 53-2025, in April 2026.
- NSF also routes reverse osmosis systems' PFOA/PFOS claims to 53 on its listings.
- WQA words claims differently, such as "Lead" and "Perfluorooctanoic Acid (PFOA)." EPA names five ANSI-accredited certifiers that test filters to these standards: CSA Group, IAPMO R&T, NSF, UL Solutions and WQA.
- A listing from any of them is a real certification.
- WQA says its own accreditation comes from ANAB and SCC.
Claims to look for
| Contaminant | Claim on the listing |
|---|---|
| Lead | Lead ReductionNSF listing wording. WQA lists it as "Lead." EPA suggests also looking for an NSF/ANSI 42 Class I particulate claim. |
| Copper | Copper ReductionNSF listing wording. WQA lists it as "Copper." |
| PFOA | PFOA ReductionNSF listing wording. NSF also files reverse osmosis systems' PFOA claims under 53. NSF says a PFAS claim means reducing PFAS below 20 ppt. EPA says current certifications do not yet show a filter reaches EPA's limits. |
| PFOA | Perfluorooctanoic Acid (PFOA)WQA listing wording for the same claim. |
| PFOA | Total PFAS ReductionNSF listing footnotes include PFOA in Total PFAS. |
| PFOS | PFOS ReductionNSF listing wording. NSF also files reverse osmosis systems' PFOS claims under 53. NSF says a PFAS claim means reducing PFAS below 20 ppt. EPA says current certifications do not yet show a filter reaches EPA's limits. |
| PFOS | Perfluorooctane Sulfonate (PFOS)WQA listing wording for the same claim. |
| PFOS | Total PFAS ReductionNSF listing footnotes include PFOS in Total PFAS. |
| PFHxS | Total PFAS ReductionNSF listing footnotes include PFHxS in Total PFAS. NSF says a PFAS claim means reducing PFAS below 20 ppt. EPA says current certifications do not yet show a filter reaches EPA's limits. |
| PFHxS | Perfluorohexane Sulfonic Acid (PFHxS)WQA listing wording for a single-compound claim. |
| PFNA | Total PFAS ReductionNSF listing footnotes include PFNA in Total PFAS. NSF says a PFAS claim means reducing PFAS below 20 ppt. EPA says current certifications do not yet show a filter reaches EPA's limits. |
| PFNA | Perfluorononanoic Acid (PFNA)WQA listing wording for a single-compound claim. |
| PFBS | Total PFAS ReductionNSF listing footnotes include PFBS in Total PFAS. No single-compound PFBS claim was found on NSF or WQA listings. |
| Other PFAS monitored in UCMR 5 | Total PFAS ReductionOf these 23, only PFHpA and PFDA are in the Total PFAS footnote on NSF listings. |
| Other PFAS monitored in UCMR 5 | Perfluoroheptanoic Acid (PFHpA)WQA listing wording. Covers PFHpA only. |
| Arsenic | Arsenic (Pentavalent)<=50 ppb ReductionNon-RO filters, including some pitchers, per NSF. Pentavalent arsenic only. |
| Arsenic | Arsenic (III) (50 ppb influent level)WQA listing wording. The only trivalent arsenic claim found. NSF's listings show none. |
| Chromium (total) | Chromium ReductionNSF listing wording. The listing does not say which form of chromium. |
| Chromium (total) | Chromium (Trivalent) ReductionNSF listing wording. NSF's claims guide also links pitchers to a 53 hexavalent chromium claim, but that search returned no products on Oct. 4, 2026. |
| Total trihalomethanes (TTHM) | Trihalomethanes (TTHM) ReductionNSF listing wording. WQA wording: "TTHM (as chloroform)." |
| Total trihalomethanes (TTHM) | VOC ReductionNSF listing footnotes say the VOC claim includes TTHM. WQA wording: "VOC (as chloroform)." |
Filters TapBuff has checked against a listing
Every certification below links to the certifier’s own listing. A filter appears here only if its listing shows NSF/ANSI 53.
- Maker’s page
Brita Tahoe Pitcher with Elite Filter (OB60, OB06)
Pitcher
- Maker’s page
Brita Tahoe Pitcher with Original Filter (OB60, OB03)
Pitcher
- Maker’s page
PUR PLUS 11-Cup Pitcher (PPT111W)
Pitcher
- Maker’s page
- Maker’s page
PUR PLUS Faucet Filtration System, Horizontal (PFM400H)
Faucet mount
- Maker’s page
Brita Elite Water Filter Faucet System (SAFF-100/FF-100)
Faucet mount
- Maker’s page
Aquasana Claryum Direct Connect (AQ-MF-1)
Under-sink carbon
- Maker’s page
- Maker’s page
- Maker’s page
- Maker’s page
AquaTru Classic (AT2000)
Countertop reverse osmosis
- Maker’s page
Sources
- NSF Standards for Water Treatment Systems, NSF. Checked Oct. 4, 2026.
- NSF/ANSI 42, 53 and 401: Filtration Systems Standards, NSF. Checked Oct. 4, 2026.
- Search for NSF Certified Drinking Water Treatment Units (standards and reduction claims lists), NSF. Checked Oct. 4, 2026.
- Contaminant Reduction Claims Guide, NSF. Checked Oct. 4, 2026.
- Forever Chemicals and the Advancement of Filtration Standards, NSF. Checked Oct. 4, 2026.
- PFAS in Drinking Water, NSF. Checked Oct. 4, 2026.
- NSF listings for the NSF/ANSI 53 "Total PFAS Reduction" claim (footnotes define Total PFAS), NSF. Checked Oct. 4, 2026.
- NSF listings for the NSF/ANSI 53 "VOC Reduction" claim (footnote lists included chemicals), NSF. Checked Oct. 4, 2026.
- NSF/ANSI 53-2025: Drinking Water Treatment Units - Health Effects uploaded (posted April 20, 2026), NSF. Checked Oct. 4, 2026.
- Find WQA Certified Products (Gold Seal listings by standard and claim), Water Quality Association. Checked Oct. 4, 2026.
- Product Certification, Water Quality Association. Checked Oct. 4, 2026.
- Fact Sheet: Reducing PFAS in Your Drinking Water with a Home Filter (April 2024), U.S. EPA. Checked Oct. 4, 2026.
- Consumer Tool for Identifying Point-of-Use and Pitcher Filters Certified to Reduce Lead in Drinking Water (EPA/600/F-24/143, June 2024), U.S. EPA. Checked Oct. 4, 2026.