Culligan MaxClear
The first gravity filter with independent certification for health contaminants: IAPMO-certified to reduce total PFAS, lead, and microplastics. Built on the ProOne platform Culligan acquired.
Jump to pick ›Boroux Legacy
From Berkey’s founders: a 3-gallon stainless system whose filters mirror the Black Berkey spec. Well built and well documented, but self-tested rather than certified.
Jump to pick ›Big Berkey
The name that defined the category, still capable off-grid. But it’s uncertified, tangled in an EPA dispute, and widely counterfeited, so buy with care.
Jump to pick ›A gravity filter needs no power and no plumbing: fill the top chamber and clean water drips into the bottom. For years the category’s weakness was certification, with every big name relying on its own lab testing. That changed when Culligan bought ProOne and launched MaxClear, the first gravity filter independently certified for PFAS, lead, and microplastics, which makes it our pick. Our three picks are above; the full field, including Berkey, Boroux, and Alexapure, is compared below.
How they compare
The gravity systems worth knowing, ordered by our assessment with independent certification weighted first. This category’s real divide isn’t capacity or looks; it’s whether a filter’s removal claims are independently certified or only self-tested. British Berkefeld and Purewell appear here for completeness but didn’t make our detail picks.
| # | Filter | Capacity | PFAS | Lead | Certified |
|---|---|---|---|---|---|
| 01 | Culligan MaxClearBest overallCeramic + carbon gravity, ex-ProOne | 2.25 or 3 gal | Cert | Cert | Cert |
| 02 | Boroux LegacyBerkey successorCarbon-block gravity, from Berkey’s founders | 3 gal (1.8 Compact) | Tested | Tested | Limited |
| 03 | Big BerkeyOff-grid classicGravity icon, availability disrupted | 2.25 gal | Tested | Tested | No |
| 04 | Travel BerkeyTravel pickGravity, portable | 1.5 gal | Tested | Tested | No |
| 05 | Alexapure ProPrepper favoriteSingle-element stainless gravity | 2.25 gal | Tested | Tested | No |
| 06 | British BerkefeldDoulton ceramic gravity | 2.25 gal | No | Tested | Limited |
| 07 | Purewell3-stage ultrafiltration gravity | 2.25 gal | No | No | Limited |
Cert = independently certified for health contaminants (IAPMO to NSF/ANSI standards) · Tested = the maker’s own lab testing, not third-party certified · Limited = certified only for aesthetics, materials, or particulates (e.g. NSF/ANSI 42 or 372), not for lead or PFAS · No = no certification or no claim. Only the two Berkeys carry our full 5-point review scores so far, shown on their cards below; see how we rank.
Our gravity picks in full
Each pick in detail, with what it does and who it’s for. The Berkeys link to our complete reviews; the others are covered here ahead of full reviews to come.
Culligan MaxClear
The certification gap that held this whole category back finally closed. Culligan acquired ProOne and relaunched its gravity line as MaxClear, with filters IAPMO-certified to NSF/ANSI standards to reduce total PFAS, lead, and microplastics, plus pharmaceuticals, pesticides, chlorine, and chloramine. No other gravity filter can say that; every rival relies on its own testing. The ceramic-and-carbon elements need no priming, and the 7-inch filters also drop into Berkey, Boroux, ProOne, and most other housings. The honest trade-off is filter life: each element is rated for about 6 months, well short of the multi-thousand-gallon claims Berkey-style elements make, so cost per gallon runs higher.
Boroux Legacy
Boroux was started by Berkey’s founders after the EPA dispute upended the original brand, and it shows: the stainless Legacy feels like the Berkey formula refined. Its Foundation filters mirror the Black Berkey spec, claim longer rated life, publish full third-party spec sheets, and fit Berkey housings too. The Compact is sized to sit under standard kitchen cabinets, a small fix countertop owners have wanted for years. The caveat is the familiar one: its only certification is NSF/ANSI/CAN 372 for lead-free materials, and its removal claims are self-tested. If you want the Berkey experience with a cleaner supply chain, this is it; if you want verified numbers, the MaxClear is the surer pick.
Big Berkey
The system that made gravity filtration famous, and still a capable off-grid unit: excellent taste, strong bacteria and cyst reduction, and elements that last for years. But the caveats have piled up. It carries no NSF/ANSI certification, its lab testing ran to a small fraction of the filter’s rated life, a 2023 EPA stop-sale order has disrupted genuine supply, and counterfeits are common. It remains a reasonable choice for emergency and off-grid use if you source a genuine unit from official channels; for everyday certified filtration, the MaxClear now does gravity better.
Travel Berkey
The smaller 1.5-gallon Berkey for travel, RVs, and one-to-three-person homes, with the same elements and the same uncertified status as the Big Berkey, so it scores the same. Great when you need filtered water anywhere with no power, but the certification and authenticity caveats carry over in full. Note that Culligan’s MaxClear and Boroux’s Foundation filters both fit Berkey housings, so an existing Travel Berkey can be upgraded to certified elements without replacing the hardware.
Alexapure Pro
A long-running favorite in the preparedness community, sold widely through emergency-supply retailers. The stainless housing is solid and the maker’s testing claims reduction of 200-plus contaminants, but those claims carry no independent certification. Its single filter element also means slower flow than the dual-element systems above, and replacement filters work out comparatively expensive per gallon over time. A serviceable emergency unit with a loyal following; for daily drinking water we’d point you to the certified MaxClear first.
How to choose a gravity filter
Gravity filters all work the same way, so the decision comes down to two questions: do you want certified removal claims, and how much water does your household draw each day. Here’s how we’d think it through.
Certification finally reached gravity filters
For years, choosing gravity meant accepting the maker’s word: Berkey, Alexapure, and Boroux all publish their own lab tests rather than independent certifications. The Culligan MaxClear broke that pattern with IAPMO certification for PFAS, lead, and microplastics. If those contaminants are why you’re filtering, certification is the whole point, and there’s now a gravity option that has it.
Gravity or reverse osmosis?
Gravity wins when there’s no outlet: off-grid cabins, emergencies, RVs, and renters who want zero installation. But if you have power, a certified countertop RO like the AquaTru removes more, including fluoride, which no gravity filter here is certified for. For everyday city-water filtration with an outlet nearby, RO is still the stronger answer.
Weighing gravity against everything else? See our best countertop filters, or the best drinking water filters overview across every type.
Common questions
What’s the best gravity water filter?
For most people, the Culligan MaxClear: it’s the only gravity filter independently certified (by IAPMO, to NSF/ANSI standards) to reduce total PFAS, lead, and microplastics, and it comes in 2.25 and 3-gallon stainless systems. If you want the classic Berkey-style experience with long-life elements, the Boroux Legacy from Berkey’s founders is the strongest uncertified option. The Big Berkey itself remains a capable off-grid unit, with real caveats.
Are gravity water filters NSF certified?
Almost none are, and that’s been the category’s biggest weakness. Berkey, Alexapure, and Boroux rely on their own lab testing, while a few carry limited certifications for materials or chlorine taste only. The exception is Culligan’s MaxClear line, which is IAPMO-certified to NSF/ANSI standards for health contaminants including PFAS and lead. Our NSF certification guide explains what those standards actually verify.
What happened to Berkey?
In 2023 the EPA issued stop-sale orders classifying Berkey’s silver-treated filters as unregistered pesticide devices, and the legal fight is still ongoing. Genuine stock has been scarce since, counterfeit elements have circulated, and the brand’s founders launched Boroux as a successor. Meanwhile Culligan acquired ProOne and launched the certified MaxClear line aimed squarely at Berkey owners. Our Big Berkey review covers the full story.
Do gravity filters remove fluoride?
Not with certification, no. Berkey requires separate PF-2 add-on filters for fluoride, and Culligan doesn’t list fluoride among MaxClear’s certified reductions. If certified fluoride removal is your goal, a reverse-osmosis system is the reliable route; see our fluoride guide and the best RO systems.
Can I put certified filters in my existing Berkey housing?
Yes, and it’s one of the best upgrades in the category. Culligan’s 7-inch MaxClear filters are designed to fit most gravity housings, including Berkey, Boroux, ProOne, Purewell, and Waterdrop systems, and Boroux Foundation filters fit Berkey housings too. That means you can keep your stainless chambers and swap in independently certified elements rather than replacing the whole unit.