The Big Berkey Water Filter System: Uncertified and Inconvenient (2023)

Since 2016, I have overseen our water-filter guides, covering both pitchers and under-sink systems. John Holecek, a former NOAA researcher, has conducted air- and water-quality testing for us since 2014. He prepared the test solutions and contracted the independent lab that Wirecutter commissioned for this guide and for our guide to water pitcher filters. That lab, EnviroMatrix Analytical, is accredited by the California Department of Health Services, and it routinely analyzes drinking water.

Big Berkey filter systems, and similar systems by Alexapure and ProOne (formerly known as Propur), are popular with people who rely on well water, which may contain contaminants that would otherwise be removed by a municipal water plant. Berkey also has a significant following among the disaster-preparedness community and government skeptics.¹ And Berkey retailers tout these systems as safety equipment for emergencies, with some estimating they can provide filtered drinking water to as many as 170 people per day.

No matter the reason for your interest in Berkey or any other water-filter systems, we should emphasize that most US municipal water is pretty clean to begin with. No filter can remove pollutants that aren’t there in the first place, so unless you have a known issue, you may not need a filter at all.

Big Berkey’s manufacturer claims that the device removes more than a hundred contaminants (far more than any other gravity-fed filter we have evaluated). Because the filter is not NSF/ANSI–certified—unlike every other filter we recommend in our other guides—we didn’t have a firm basis for comparison with the other filters we have tested in the past. So we decided to conduct independent tests to attempt to reproduce some of these results.

To test these claims, as we do for our filter-pitcher testing, John Holecek prepared so-called challenge solutions and ran them through the Big Berkey system (fitted with the Black Berkey filters). Then he sent samples of the solutions and the filtered water to an independent lab, EnviroMatrix Analytical, accredited by the state of California for analysis. For the Big Berkey testing, he prepared two solutions—one heavily laden with dissolved lead, the other with chloroform. These would provide an indication of the filters’ overall performance on heavy metals and organic compounds.

John prepared challenge samples to match or exceed the contaminant concentrations used in NSF/ANSI certification (150 ug/L for lead and 300 ug/L for chloroform). After confirming that the filters were installed and performing correctly, according to Berkey’s dye test (video), he ran a gallon of contaminated solution through the Berkey and discarded the filtrate (the water and whatever else that had passed through the filter). For the contaminated solution measurements, he filtered a total of two additional gallons through the Berkey, taking a control sample from the second gallon and collecting two test samples of the filtrate from it. The control and filtrate samples were then sent to EnviroMatrix Analytical for testing. Because chloroform is highly volatile—it “wants” to evaporate and combine with other compounds present—John mixed the chloroform into the contaminant solution immediately prior to filtering.

At EnviroMatrix Analytical, the chloroform and any other volatile organic compounds (or VOCs) were measured using a gas chromatography-mass spectrometer (GC-MS). The lead was measured using an inductively coupled plasma-mass spectrometry (ICP-MS) device, following EPA method 200.8.

EnviroMatrix Analytical’s results partially contradicted and partially supported New Millennium’s claims. The Black Berkey filters showed poor reduction of chloroform. On the other hand, they performed spectacularly well on lead reduction. (See the full results in the next section.)

We shared our lab’s results with Jaime Young, a chemist and New Jersey–licensed owner/operator of the water analysis lab (then known as Envirotek) commissioned in 2014 by New Millennium Concepts (manufacturer of the Big Berkey system) for its own testing of its Black Berkey filters.² Young corroborated our findings on both chloroform and lead.

New Millennium has commissioned other tests in the past, including one conducted in 2012 by the County of Los Angeles’ Environmental Toxicology Laboratory of the Department of the Agricultural Commissioner/Weights and Measures; this one does list chloroform (PDF) among the contaminants the Black Berkey removed to the department’s standard (EPA, not NSF/ANSI). Since that 2012 test, toxicology was shifted to the Los Angeles Department of Public Health. We reached out to the DPH, and it confirmed the original report’s legitimacy. But New Millennium describes Young’s test as its “latest round,” and his results are the most recently listed on the Berkey Water Knowledge Base, the separate site New Millennium maintains for listing its test results and answering frequently asked questions.

Wirecutter’s, Young’s, and Los Angeles County’s test protocols are mutually inconsistent. And because none of them conform to the NSF/ANSI standards, we don’t have a standard basis for comparing the results.

Therefore, we are not heavily leaning on our test results in our general take on the Big Berkey system. The Big Berkey has enough ease-of-use and cost issues that we would recommend a mainstream gravity-fed filter pitcher over it to most readers, even if the Berkey does everything New Millennium claims it can do as a filter.

We also cut open a pair of Black Berkey filters to see how they are constructed and to look for evidence that, as Berkey marketing claims, they contain “at least” six different filtering elements. We found that though the Berkey filters are larger and denser than filters from Brita and 3M Filtrete, they appear to share their filtration mechanisms: activated charcoal impregnated with an ion-exchange resin.

The Berkey filter system belongs to the broad class of gravity-fed water filters. These simple devices use gravity to draw source water from an upper chamber, through a fine-pored filter; the filtered water is collected in a lower chamber from which it can be dispensed. It’s an effective, widely used method—filter pitchers are a familiar example.

The Berkey filters showed strong performance on lead-contaminated drinking water. In our test they reduced lead levels from 170 ug/L to just 0.12 ug/L, a measurement that far exceeds the NSF/ANSI certification requirement of reducing lead from 150 ug/L to 10 ug/L or less.

But in our test on chloroform, the Black Berkey filters performed poorly, lowering it by just 13% in our test sample, from 150 ug/L to 130 ug/L. NSF/ANSI requires a 95% reduction, from 300 ug/L to 15 ug/L or less. (Our test solution was mixed to the NSF/ANSI standard of 300 ug/L, but chloroform’s volatility means that it rapidly forms new compounds or evaporates—hence the drop to 150 ug/L at the time of the test. But EnviroMatrix Analytical’s tests also captured other volatile organic compounds that chloroform can create, so we are confident that the results are accurate.) Jaime Young, the New Jersey–licensed water analysis engineer who conducted New Millennium Concepts’ most recent round of testing, also got poor performance on chloroform from the Black Berkey filters.

New Millennium Concepts, however, claims—right on the box the filters come in—that the Black Berkey filter reduces chloroform by 99.8%, to “below lab detectable limits.” (That number appears to be based on the testing done by the Los Angeles County lab in 2012. Its test results [PDF] are available at the Berkey Water Knowledge Base, linked to on—but not part of—Berkey’s main site.)

To be abundantly clear: Neither we nor Envirotek nor Los Angeles County reproduced the entire NSF/ANSI Standard 53 protocol, used for gravity-fed filters like the Black Berkey.

For our part, we had our lab run tests after the Black Berkeys had already filtered several gallons of challenge solution prepared to NSF/ANSI concentrations. But NSF/ANSI certification requires that gravity-fed filters pass through twice their rated capacity of challenge solution before testing. In the Black Berkey filter’s case, that would mean 6,000 gallons.

Like us, Jaime Young prepared his test solutions to NSF/ANSI Standard 53, but he did not run the 6,000 gallons of contaminant solution through the filters that the complete Standard 53 protocol would have required of the Black Berkeys. He reported that the filters gave exceptional performance on lead in his test, too, corroborating our own finding. However, he said that they stopped meeting the NSF removal standard after approximately 1,100 gallons of filtering—barely more than a third of the 3,000-gallon lifespan New Millennium claims for the Black Berkey filters.

Los Angeles County followed a separate EPA protocol, which involved passing only single, 2-liter samples of the challenge solutions through the filters. Unlike us or Young, the county found that the Black Berkey filters removed chloroform to its test standard, in its case by greater than 99.8%, to less than 0.5 ug/L from 250 ug/L.

The inconsistency of our test results, compared with the results from the two labs commissioned by Berkey, left us hesitant to recommend this filter, especially when you can find other independently certified options that put all of these open questions to rest.

Overall, our testing experience reinforces our position that we recommend water filters with NSF/ANSI certification, which the Berkey does not have. That’s because NSF/ANSI standards for certification are exceptionally rigorous, and they are also transparent: Anyone can read them on NSF’s site. The independent labs licensed to conduct NSF/ANSI certification tests are themselves strictly accredited. We spoke with a representative from NSF while reporting this guide, and we learned that it would cost well over $1 million to conduct certification testing for all of the substances New Millennium Concepts claims that the Black Berkey filters remove. New Millennium states that it considers NSF certifications unnecessary, and it cites cost as another reason the testing has not been done.

But even leaving actual filtration performance aside, this filter has enough practical concerns for us to easily recommend one of our other water-filter picks before recommending the Big Berkey. For one, the Berkey system is far more expensive to buy and maintain than any of our recommended filters. And unlike our recommended filters, the Berkey is also large and obtrusive. It is designed to sit on the countertop. But because it’s 19 inches tall, it won’t fit under many wall cabinets, which are typically set 18 inches above the countertop. The Berkey is also too tall to fit in most refrigerator configurations. So it’s unlikely that you’ll be keeping water cold in the Berkey (something that is easy to do with our filter pitcher picks). New Millennium Concepts offers a 5-inch stand to make it easier to fit glasses under the Big Berkey’s spigot, but those cost extra and add more height to the already towering contraption.

A Wirecutter writer who owned a Big Berkey in the past sent a note about his experience: “Besides the unit being absurdly large, it’s also somewhat easy to overfill the top reservoir if you forget to empty the bottom tub. Fully filled, the top reservoir is somewhat heavy and unwieldy, and it immediately starts filtering. So you have to lift it up to get clearance for the carbon filters (which are long and delicate) and then place it into the bottom pot all before it starts leaking all over your floor or counter.”

Another Wirecutter editor owned a Big Berkey (with the company’s alternative ceramic filters) but soon stopped using it. “It was a gift from my spouse because I’d seen one at a friend’s house and thought that the water that came out tasted wonderful,” he said. “Living with one was an entirely different matter. The countertop footprint, both horizontally and vertically, was enormous and awkward. And the kitchen sink where we lived at the time was so small that washing it was a cumbersome chore.”

We also see a lot of complaints from owners about algal and bacterial growth and, more generally, slime building up in their Big Berkeys. New Millenium Concepts acknowledges the issue and recommends adding its Berkey Biofilm Drops to the water being filtered. And it’s enough of a problem that many Berkey dealers have a whole page devoted to it.

Many dealers acknowledge that bacterial growth can become an issue, but their frequent claim of this starting after a few years of use wasn’t the case for our editor. “It began after just under one year,” he said. “The water tasted musty and a mildew smell began to form in both the upper and lower chambers. I’d wash it thoroughly, flushing the filters and detaching them to get into all the tiny connection points, and I made sure to even clean inside the spigot. The taste of the water would return to normal for about two or three days before becoming musty again. I ended up putting the Berkey on the curb, which I feel terrible about.”

Thoroughly removing the algae-bacteria slime from Black Berkey filters involves scouring their surfaces with Scotch-Brite, doing the same for the upper and lower tanks, and finally running a bleach solution through the filters. That is a lot of maintenance for something meant to give people peace of mind about their water.

Most gravity-fed filters employ two different materials to remove contaminants from water. Activated charcoal adsorbs or chemically binds with organic compounds, which include petroleum-based fuels and solvents, many pesticides, and many pharmaceuticals. An ion-exchange resin removes many dissolved metals from water by exchanging toxic heavy metals (like lead, mercury, and cadmium) for lighter, essentially harmless ones (like sodium—a chief component of table salt).

Our picks for pitcher filters (from Brita) and under-sink filters (from 3M Filtrete) are both constructed this way. New Millennium Concepts does not disclose what the Black Berkey filters are made of, but some retailers make claims about their construction, including this one from TheBerkey.com: “Our Black Berkey Purification elements are composed of a proprietary formulation of more than six different media types including high grade coconut shell carbon, all constructed into a very compact matrix containing millions of microscopic pores.” When we cut open a pair of Black Berkey filters, they appeared to be constructed of an activated charcoal block impregnated with an ion-exchange resin. Jaime Young corroborated this observation.

This article was edited by Harry Sawyers.