Best Drinking Water Filters
The best drinking water filter has third-party test data showing which contaminants it removes, by what percentage, and for how many gallons. Few brands publish all three, and some filters certified only for TDS or chlorine are marketed as removing dozens of contaminants. I pulled every NSF, WQA, and IAPMO certification listing for the brands below, added independent lab reports and brand data sheets, and ranked each filter by how many contaminants it's proven to remove. Certified results count most, independent lab results less, and in-house testing least, as explained in my methodology below.
By Dr. Meg Christensen | Physician-founder of Interior Medicine, a non-toxic home resource built on her background in medicine, biochemistry, epidemiology, and clinical research.
Updated October 5, 2026
| Rank | Brand and product | Type | Evidence | Score | Contaminants verified | Capacity |
|---|---|---|---|---|---|---|
| 1 | AquasanaSmartFlow RO | RO (under-sink) | Certified | 17 | 17Chlorine, chloramine, lead, mercury, cadmium, barium, arsenic, chromium-6, fluoride, nitrate, radium, PFOA/PFOS, VOCs, cyst, TDS, 15 pharmaceuticals, microplastics | 250 gal |
| 2 | AquaTruCarafe | RO (countertop) | Certified | 16 | 16Chlorine, chloramine, lead, barium, arsenic, chromium-6, fluoride, nitrate, perchlorate, radium, PFOA/PFOS, VOCs, cyst, TDS, 15 pharmaceuticals, microplastics | 300 gal |
Only AquaTru model certified for hexavalent chromium by name. Pass/fail only, no percentages published. | ||||||
| 3 | AquaTruClassic (regular + smart) | RO (countertop) | Certified | 15 | 15Chlorine, chloramine, lead, barium, arsenic, fluoride, nitrate, perchlorate, radium, PFOA/PFOS, VOCs, cyst, TDS, 15 pharmaceuticals, microplastics | 600 gal |
NSF 58 claim reads 'Chromium' without saying hexavalent or trivalent, so chromium-6 is not credited. | ||||||
| 4 | AquaTruUnder Sink | RO (under-sink) | Certified | 14 | 14Chlorine, chloramine, lead, barium, arsenic, fluoride, nitrate, perchlorate, radium, PFOA/PFOS, VOCs, TDS, 15 pharmaceuticals, microplastics | 360 gal |
No cyst claim, even though the Classic's RO element (AT2002) carries one. ATU200 is on the same listings with the same claims (RO element AT2005). 'Chromium' type unspecified, not credited. | ||||||
| 5 | CloudCloud RO | RO (under-sink) | Mixed: certified + lab | 9.25 | 12Chlorine, chloramine, lead, mercury, cadmium, barium, arsenic, chromium-6, fluoride, nitrate, PFOA/PFOS, TDS | Not rated (common for RO) |
VOC row repeats the free-particle numbers (50,500 in, 11 out), which looks like a possible sheet error, so not trusting as a VOC result. Fluoride recomputed to 99.5% (sheet says 100%). Lead challenges in the NSF 53 section (0.03 and 0.06 mg/L) are below the 0.15 mg/L NSF protocol. | ||||||
| 6 | AquasanaClaryum 3-Stage Max Flow | Non-RO (under-sink) | Certified | 9 | 9Chlorine, chloramine, lead, mercury, PFOA/PFOS, VOCs, cyst, 15 pharmaceuticals, microplastics | 800 gal |
Claryum data sheets match each other almost exactly despite different capacities and flow rates; they differ only on MTBE (3-Stage 83.5% vs 85.5%) and nonylphenol (Clean Water Machine 95.5% vs 92.3%). MTBE here: 85.5%. | ||||||
| 7 | AquasanaClaryum Direct Connect | Non-RO (under-sink) | Certified | 9 | 9Chlorine, chloramine, lead, mercury, PFOA/PFOS, VOCs, cyst, 15 pharmaceuticals, microplastics | 784 gal |
| 8 | AquasanaClaryum 3-Stage | Non-RO (under-sink) | Certified | 9 | 9Chlorine, chloramine, lead, mercury, PFOA/PFOS, VOCs, cyst, 15 pharmaceuticals, microplastics | 600 gal |
Claryum data sheets match each other almost exactly despite different capacities and flow rates; they differ only on MTBE (3-Stage 83.5% vs 85.5%) and nonylphenol (Clean Water Machine 95.5% vs 92.3%). MTBE here: 83.5%. | ||||||
| 9 | AquasanaClaryum 2-Stage | Non-RO (under-sink) | Certified | 9 | 9Chlorine, chloramine, lead, mercury, PFOA/PFOS, VOCs, cyst, 15 pharmaceuticals, microplastics | 500 gal |
Claryum data sheets match each other almost exactly despite different capacities and flow rates; they differ only on MTBE (3-Stage 83.5% vs 85.5%) and nonylphenol (Clean Water Machine 95.5% vs 92.3%). MTBE here: 85.5%. | ||||||
| 10 | AquasanaClean Water Machine | Non-RO (countertop) | Certified | 9 | 9Chlorine, chloramine, lead, mercury, PFOA/PFOS, VOCs, cyst, 15 pharmaceuticals, microplastics | 300 gal |
| 11 | CulliganZeroWater pitchers and dispensersHeads-up: Filter rated for only 20 gallons (40 in the ZEROD52) | Non-RO (pitcher/dispenser) | Certified | 8.87 | 9Chlorine, lead, mercury, cadmium, chromium-6, fluoride, nitrate, Total PFAS, 13 pharmaceuticals | 20 gal |
| 12 | Clearly Filtered3-Stage Under-SinkHeads-up: Replacement filter set costs $409.50 | Non-RO (under-sink) | Independent lab | 8.65 | 12Chlorine, chloramine, lead, mercury, cadmium, barium, arsenic, chromium-6, fluoride, 9 PFAS, VOCs, 8 pharmaceuticals | 2,000 gal |
Results are 'maximum removal,' the most flattering reporting method. Pharmaceutical challenges very low (0.2–2.6 ng/L). | ||||||
| 13 | Clearly FilteredUniversal Inline Fridge Filter | Fridge | Independent lab | 8.65 | 12Chlorine, chloramine, lead, mercury, cadmium, barium, arsenic, chromium-6, fluoride, 9 PFAS, VOCs, 8 pharmaceuticals | 365 gal |
Same table as the under-sink system with the same test date; only two cells differ (2,4-DB >99.69 vs >99.96; a trimethylbenzene challenge 9.89 vs 98.9). Looks like one test presented for two products with different capacities (365 vs 2,000 gal). Maximum-removal reporting. | ||||||
| 14 | BorouxLegacy / countertop gravity system | Non-RO (gravity) | Mixed: certified + lab | 8.35 | 11Chlorine, chloramine, lead, mercury, cadmium, chromium-6, uranium, Total PFAS, VOCs, 12 pharmaceuticals, microplastics | Not rated |
Only particulate and microplastics are certified; the rest is lab-tested. Several contaminants tested to low volumes per filter: gross beta 50 gal, VOCs 200, Cr-6 250, PFAS 400. Nonylphenol row repeats the chloroform values (copy error), so it isn't counted. Not tested: arsenic, fluoride, nitrate, barium, cyst. | ||||||
| 15 | LifeStrawHome pitchers and dispensers | Non-RO (pitcher/dispenser) | Mixed: certified + lab | 8.1 | 9Chlorine, lead, mercury, cadmium, barium, PFOA/PFOS, cyst, 9 pharmaceuticals, microplastics | 40 gal |
WQA lists only the Home Glass 7-Cup pitcher; the same filter set is used in every Home product. PFOA/PFOS and barium are brand-reported lab results not included in the WQA results. Carbon filter rated 40 gal; membrane 1,000 gal. | ||||||
| 16 | WaterdropG3P600 / G3P800 | RO (under-sink) | Certified | 8 | 8Chlorine, lead, cadmium, barium, fluoride, radium, PFOA/PFOS, TDS | 1,100 gal |
Brand-supplied certificate was outdated (showed Cr-6 + selenium). Spec sheet page 2 shows uncertified results with no lab named. | ||||||
| 17 | HydrovivDrinking Water System | Non-RO (under-sink) | Certified | 7.93 | 8Chlorine, chloramine, lead, Total PFAS, VOCs, cyst, 14 pharmaceuticals, microplastics | 500 gal |
Chloramine is certified only on the REP-49oZIP cartridge. REP-29oZIP is on the 42 listing only, with no health claims. Older SRS models have narrower claims. No percentages published. | ||||||
| 18 | BritaHub countertop | Non-RO (countertop) | Certified | 7 | 7Chlorine, chloramine, lead, mercury, VOCs, 15 pharmaceuticals, microplastics | 120 gal |
VOC is certified by IAPMO; everything else by WQA. | ||||||
| 19 | WaterdropG3 (base) | RO (under-sink) | Certified | 6 | 6Chlorine, cadmium, chromium-6, fluoride, PFOA/PFOS, TDS | 1,100 gal |
Certified for chromium-6 and selenium instead of the G3P models' lead, barium and radium. | ||||||
| 20 | BritaElite pitcher/dispenser filter | Non-RO (pitcher/dispenser) | Certified | 6 | 6Chlorine, lead, mercury, cadmium, 15 pharmaceuticals, microplastics | 120 gal |
Claims depend on the pitcher. In the Classic OB01, Everyday OB46, Lake, Oceania and Stainless Steel pitchers, the 401 claim drops to microplastics only; in the Classic and Everyday OB46, NSF 53 also loses cadmium, carbon tetrachloride and endrin. No PFAS claim. WQA notes it was tested for fluoride non-removal. | ||||||
| 21 | CulliganMaxClear gravity | Non-RO (gravity) | Certified | 5.47 | 6Chlorine, chloramine, lead, Total PFAS, 7 pharmaceuticals, microplastics | 50 gal |
| 22 | WaterdropFridge filters, Plus line | Fridge | Certified | 5 | 5Lead, mercury, cyst, 15 pharmaceuticals, microplastics | 300 gal |
The WDP-F02 cartridge itself is certified only for particulate under NSF 42; chlorine is certified on sibling cartridges, not the Plus cartridge. No PFAS claim. | ||||||
| 23 | WaterdropED01 gravity | Non-RO (gravity) | Certified | 5 | 5Chlorine, lead, mercury, 15 pharmaceuticals, microplastics | 200 gal |
ED02–ED04 drop microplastics and particulate. ED01A variants (WD-EDFA) carry chlorine, taste and odor only. No PFAS claim. | ||||||
| 24 | ProOneGravity system (best case: G3.0 filter) | Non-RO (gravity) | Certified | 5 | 5Chlorine, chloramine, lead, Total PFAS, microplastics | 50 gal |
Choose the G3.0 filter; it is the only ProOne element on the listings. 50 gal per filter (100 with 2, 150 with 3 in the Big+). Brand-supplied certificates were outdated: the old 42 certificate showed materials safety only. | ||||||
| 25 | iSpringRCC7 platform, Nanjing listings | RO (under-sink) | Certified | 5 | 5Lead, cadmium, barium, fluoride, TDS | Not rated (common for RO) |
Same module names as the TDS-only Taiwan listing below, but a different factory and far broader claims; a buyer can't tell from the product name which applies. NSF 58 only, so no certified chlorine, PFAS, VOC or pharmaceutical claims. | ||||||
| 26 | WaterdropFridge filters, OEM-numbered | Fridge | Certified | 4.4 | 5Chlorine, lead, mercury, cyst, 6 pharmaceuticals | 200 gal |
Claims vary by cartridge (WDP-FQROPF has only lead, mercury, cyst, a few organics and 6 of 15 401 compounds); scored on the narrower set. Same filters sold as AquaCrest, Maxblue, Filterlogic and others. | ||||||
| 27 | BritaFaucet Mount | Non-RO (faucet) | Certified | 4.4 | 5Chlorine, lead, VOCs, 6 pharmaceuticals, microplastics | 100 gal |
Also asbestos, chlordane, toxaphene. | ||||||
| 28 | AquasanaHealthShield | Whole house (non-RO) | Mixed: certified + in-house | 3.13 | 5Chlorine, chloramine, 5 PFAS, VOCs, 2 pharmaceuticals | 165,000 gal |
Certified for 5 named PFAS, not the 7-compound Total PFAS claim. Chlorine and chloramine were tested in Aquasana's own lab; the data sheet says WQA did not evaluate them. | ||||||
| 29 | BritaPlus filter | Non-RO (pitcher/dispenser) | Certified | 3 | 3Chlorine, mercury, cadmium | 40 gal |
Also copper and 6 named organics (benzene, ethylbenzene, tetrachloroethylene, toluene, 1,2,4-trichlorobenzene), no VOC claim. | ||||||
| 30 | BritaRefillable filter | Non-RO (pitcher/dispenser) | Certified | 3 | 3Chlorine, mercury, cadmium | 40 gal |
Also copper and zinc. | ||||||
| 31 | BritaStandard filter | Non-RO (pitcher/dispenser) | Certified | 3 | 3Chlorine, mercury, cadmium | 40 gal |
Also copper and zinc. No lead claim. | ||||||
| 32 | RorraCountertop System and Filtered Pitcher | Non-RO (gravity/pitcher) | Independent lab | 2.55 | 4Chlorine, lead, Total PFAS, 6 pharmaceuticals | 200 gal |
One-time qualification tests, not certification; every NSF page says it does not represent NSF Certification. Lead: all effluents read ND(10) µg/L by ICP-AES, above the 5 µg/L pass limit, so the data can't show a pass even though NSF marked PASS; 93% is a floor. 401 covers Group 3 only (6 compounds), and Filter 1 and 2 report identical values for several compounds. Rorra's site labels a 'Microplastics (NSF/ANSI 401)' result of 97.3% at 200 gal, but its Full Report link opens an NSF 42 Particulate Class I report (J-00500687), not a 401 microplastics test, so microplastics is not credited. That particulate report has two sample points, and the one labeled 50% capacity sits at 117–134 L (31–35 gal), not half of the 200 gal rating. | ||||||
| 33 | WaterdropX-series | RO (under-sink) | Certified | 2 | 2Chlorine, TDS | 1,200 gal |
| 34 | British BerkefeldGravity system (best case: Ultra Sterasyl or SS2 Ultra Fluoride) | Non-RO (gravity) | Certified | 2 | 2Cyst, microplastics | Not rated |
NSF-listed only for particulate, cyst, turbidity and microplastics. The SS2 Ultra Fluoride element carries the same four claims and is not certified for fluoride or any chemical contaminant. Fluoride is certifiable under NSF 53 (Culligan ZeroWater's pitcher filter holds that claim), so this is a gap in Berkefeld's listing, not in the standards. | ||||||
| 35 | Waterdrop10U / 15U / 17U under-sink families | Non-RO (under-sink) | Certified | 1 | 1Chlorine | 11,000 gal |
Chlorine, taste and odor only, despite large gallon numbers (family ranges 950–37,070). | ||||||
| 36 | WaterdropCountertop (faucet-connected) CTF | Non-RO (countertop) | Certified | 1 | 1Chlorine | 8,000 gal |
| 37 | BritaStream filter | Non-RO (pitcher) | Certified | 1 | 1Chlorine | 40 gal |
Only health claim is 1,2,4-trichlorobenzene; the data sheet prints its units as ppm, almost certainly ppb. | ||||||
| 38 | iSpringRCC7 platform, Taiwan listings | RO (under-sink) | Certified | 1 | 1TDS | Not rated (common for RO) |
TDS only, yet iSpring's pages for these models advertise the full 9-claim list. | ||||||
| 39 | iSpringRO500 tankless | RO (under-sink, tankless) | Certified | 1 | 1TDS | Not rated (common for RO) |
| 40 | WaterdropG5 / RG / HQ / SQ platforms | RO (under-sink) | Certified | 1 | 1TDS | Not rated (common for RO) |
| 41 | WaterdropCountertop RO | RO (countertop) | Certified | 1 | 1TDS | Not rated (common for RO) |
The A1 is not on W-17249, so it is treated as uncertified. | ||||||
| 42 | Clearly FilteredFiltered Water Pitcher | Non-RO (pitcher) | Independent lab | 0.75 | 1Chlorine | 100 gal |
Data sheet claims NSF 42 certification for chlorine; no listing in the project yet, so scored as lab tested. | ||||||
| 43 | AquasanaRhino Max Flow | Whole house (non-RO) | In-house testing | 0.5 | 1Chlorine | 1,000,000 gal |
Tested to NSF 42 for chlorine, not certified, with no lab named. Per-sample results fall to ~92% near end of life. WH-1000 and WH-1010 share one data table (same values, same errors) despite different flow rates (14 GPM here). | ||||||
| 44 | AquasanaRhino | Whole house (non-RO) | In-house testing | 0.5 | 1Chlorine | 1,000,000 gal |
Tested to NSF 42 for chlorine, not certified, with no lab named. Per-sample results fall to ~92% near end of life. WH-1000 and WH-1010 share one data table (same values, same errors) despite different flow rates (7 GPM here). | ||||||
| 45 | DurynGlass pitcher with carbon block | Non-RO (pitcher) | Independent lab | 4.5 | 6Chlorine, lead, mercury, cadmium, Total PFAS, cyst | Not rated |
Placed last among tested filters. The PFAS report says 300 L was tested, but the data stops at 35 L (9.25 gal) with two sample points after the flow collapsed, and its text says 'metals were retained.' The metals report has two sample points to 150 L, and its text (TDS 250) and table (TDS 50) disagree. The chlorine report is labeled EuroGuard. No rated capacity established. | ||||||
| 46 | iSpringWRO4000 whole-house RO | Whole house (RO) | None | 0 | 0None verified | Not rated |
| 47 | WaterdropWhole-house systems | Whole house (non-RO) | None | 0 | 0None verified | Not rated |
| 48 | SpringWellWhole-house systems (CF series, PFAS filter) | Whole house (non-RO) | None | 0 | 0None verified | Not rated |
Only materials-certified components (NSF 42, 61, 53 materials claims); rep could not provide a certificate. No contaminant certification or lab report. | ||||||
| 49 | iSpringOther under-sink RO platforms | RO (under-sink) | None | 0 | 0None verified | Not rated |
Product pages claim the same broad removal as certified models. | ||||||
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Looking for something specific? If you don't see the product or brand you're curious about, you can request a review. I’m adding more brands (APEC, Sorso, SharkNinja, Aarke, Belon, Berkey) soon, as well as more fridge, faucet, and whole-house filtration options, but let me know if you’d like to see others. If you want to take a deeper dive, my free course covers how to evaluate products and think about non-toxic living from a birds-eye view.
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Methodology: How I Evaluate How Effective a Home Water Filtration System Is
The most reliable way to tell if a water filter removes contaminants, ranked from most to least trustworthy:
Highest: Full third-party certification from an accredited certification body. This is not just a single set of test results done once on one system. It’s ongoing and thorough and also requires factory audits, testing on random products pulled from stock or the market, periodic re-testing, and a public listing that can be revoked.
NSF: NSF develops the standards and does testing and certification.
WQA or IAPMO: Both are accredited to certify to the same NSF/ANSI standards. A WQA or IAPMO certification is equivalent to an NSF certification.
High Rating: A one-time third party test report. These are legitimate, just lack the ongoing and random surveillance of full certification. They just lack the ongoing audits and retesting of full certification. Brands often choose this route because it costs less and is faster.
NSF: can run one-time tests without certifying the product. The report will say it does not represent NSF certification.
IAPMO R&T New Jersey lab: Like NSF, IAPMO can run one-time test reports without certification.
SGS: a major worldwide testing lab.
Other named, accredited labs: Look for ISO/IEC 17025 accreditation, the international standard for testing labs.
Moderate: In-house testing. Results from the brand's own lab, or from a lab it doesn't name. No independent party checked the method, the contaminant levels used, or whether the filter held up for its full rated gallons.
In-House Performance Data Sheet: can be legitimate; look into the details to see if tests were done according to NSF standards or changed.
Low: Certified components only. One part, such as a carbon block, is certified to reduce a contaminant, but the finished filter system was never tested or certified. A component can perform differently once it's inside a particular housing at a particular flow rate.
NSF Certified Components: this is most common.
Lowest: Materials-only certifications, named media, and marketing claims
Materials-only certification: This is what NSF 372 is. Some components are certified "for material requirements only." That means the part won't leach harmful substances into your water. It says nothing about what the filter removes, yet brands often present it as if it were a filtration certification. NSF 372 means the filter itself doesn’t contain lead. It doesn’t mean it can remove lead from your water.
Named filtration media: Some brands cite media like KDF, which is a legitimate filtration media. The problem is you don't know how much media is in the filter, how dense it is, or whether water actually moves through it or sneaks around the edges. Testing is the only way to see that it works.
Long lists of contaminants reduced: A longer list doesn't mean a better filter. Brands may list contaminants they assume the media removes, or rely on in-house tests run for a very short period or at a low flow rate.