Clearly Filtered vs Berkey: Which Removes More Contaminants?

Both filters work. That’s the honest answer — and also where most comparisons stop, leaving you with no real guidance. The question that actually matters isn’t “which one filters water?” but rather “which one filters your water problems?” Clearly Filtered and Berkey use fundamentally different filtration chemistry, and choosing the wrong one based on a contaminant list alone could mean you’re spending $200–$400 on a filter that misses the specific thing you’re worried about.

Here’s the angle most review articles skip entirely: contaminant count is a marketing number, not a safety metric. Berkey’s Black filters claim to reduce over 200 contaminants. Clearly Filtered pitchers claim over 365. But the number of contaminants reduced tells you almost nothing useful unless you know which contaminants, at what reduction percentage, and whether those reductions were verified by an independent lab against NSF/ANSI testing protocols. That gap between the marketing claim and the verified claim is where the real comparison lives.

Why Contaminant Count Is a Misleading Way to Pick a Filter

Picture this: you’ve just received your well water test results showing elevated arsenic at 0.018 mg/L — above the EPA’s maximum contaminant level of 0.010 mg/L. You need a filter that specifically handles arsenic, not one that handles 365 things you don’t have. Choosing based on the highest contaminant count in that situation is like hiring a contractor because they own the most tools, without checking if any of those tools are the ones you actually need for your job.

The contaminant lists on filter marketing pages also mix verified reductions with tested reductions without always distinguishing them clearly. Clearly Filtered submits its pitcher to independent NSF/ANSI Standard 42 and Standard 53 testing protocols for many of its claims, and publishes third-party lab reports. Berkey, notably, is not NSF certified — the company relies on its own internal testing and independent lab results, but those results aren’t validated through the NSF certification process that requires ongoing product audits. That distinction matters more than any headline number.

This close-up comparison of the Clearly Filtered pitcher and a Berkey Black filter element shows the physical differences in media design — a detail that helps explain why each system excels at different contaminant categories despite both being gravity-fed filtration options.

How Each Filter Actually Works Under the Hood

Clearly Filtered pitchers use a three-stage filtration process built around activated carbon, ion exchange resin, and a sub-micron mechanical filter layer. The activated carbon handles chlorine, chloramines, VOCs, and taste/odor compounds via adsorption — contaminants stick to the carbon’s enormous surface area as water passes through. The ion exchange component targets heavy metals like lead and cadmium by literally swapping charged contaminant ions for harmless ones. This layered approach is why Clearly Filtered claims greater than 99.5% reduction of lead at concentrations well above 0.015 mg/L, verified under NSF/ANSI Standard 53 challenge water conditions.

Berkey Black filters work differently. They use a pressed carbon block made from a proprietary mix of media — primarily coconut shell-based activated carbon combined with ion exchange material — in a gravity-fed stainless steel housing. The slow gravity flow rate is actually a feature, not a bug: water spending more contact time with the media improves adsorption of smaller molecules like pharmaceuticals and fluoride (though fluoride removal requires the separate PF-2 fluoride filters added below the Black elements). The mechanism favors thorough reduction of biological contaminants, heavy metals, and chlorine compounds, but the lack of NSF certification means you’re trusting the lab reports Berkey publishes rather than an independent verification body’s ongoing audits.

Which Specific Contaminants Does Each Filter Handle Better?

This is where the comparison stops being abstract and starts being useful. The table below breaks down how each system performs on the contaminants that US homeowners most commonly need to address, based on published lab data and independent testing:

Contaminant	Clearly Filtered Pitcher	Berkey Black Filter
Lead (above 0.015 mg/L)	>99.5% reduction (NSF/ANSI 53 verified)	>99.9% claimed (internal/independent lab, not NSF certified)
PFAS / PFOA / PFOS	>99% reduction (third-party verified)	Reduction claimed but less documented for PFAS specifically
Chloramines	Reduces effectively via carbon + ion exchange	Reduces effectively; slow gravity flow aids contact time
Arsenic (0.010 mg/L MCL)	Up to 99.3% reduction claimed	Reduces arsenic; PF-2 elements improve performance
Fluoride	Not a primary strength without add-ons	Requires separate PF-2 add-on filters (~$50–$60)
Bacteria / Pathogens	Not designed for microbiological removal	Claims up to 99.9999% (6-log) reduction of bacteria

The pathogen row is one of the most important differentiators here. Clearly Filtered is designed for municipal tap water where bacteria have already been treated — it’s not a purifier for microbiologically unsafe water. Berkey, by contrast, markets its Black filters as capable of addressing biological contamination, which is why it’s popular in emergency preparedness communities and for use with untreated well or surface water. If your household is on well water and you’ve had coliform detections, that difference alone may decide the question for you.

PFAS deserves a separate mention because it’s the contaminant people are most concerned about right now. Clearly Filtered has published more granular independent lab data on specific PFAS compounds — including PFOA, PFOS, and several GenX compounds — than Berkey has. That doesn’t mean Berkey doesn’t reduce PFAS, but if PFAS is your primary concern, the documentation trail is stronger on the Clearly Filtered side.

What the Flow Rate and Capacity Differences Mean for Real Daily Use

Berkey systems are gravity-fed into large stainless steel tanks — the Big Berkey holds 2.25 gallons, the Royal Berkey holds 3.25 gallons. Fill the top chamber, walk away, come back in 30–60 minutes to filtered water. The flow rate runs roughly 1 gallon per hour with a standard two-filter setup, though adding more Black filter elements speeds this up. For a household that doesn’t mind the batch-fill routine and wants a countertop unit that requires no plumbing whatsoever, this works fine. The stainless steel body also lasts essentially indefinitely — you’re only ever replacing filter elements, which are rated for up to 3,000 gallons each.

Clearly Filtered pitchers hold about 10 cups and filter faster — most users report roughly 2–3 cups per minute under normal conditions, though this slows as the filter ages. The filter itself is rated for 100 gallons before replacement, which translates to about every 2–4 months for an average household. That’s a meaningful cost difference from Berkey’s 3,000-gallon element lifespan. Replacement Clearly Filtered filters run around $55–$65 each, so a household going through three or four per year is spending roughly $200 annually on media alone — not a dealbreaker, but worth calculating honestly before you buy.

Pro-Tip: Before buying either filter, run a basic water test — even a $30 mail-in test for lead, PFAS, nitrates, and bacteria — so you’re matching the filter’s actual strengths to your actual water problems. A filter that reduces 365 contaminants you don’t have is less valuable than one that knocks out the two things your water test flagged.

How Do the Total Costs Compare When You Factor In Everything?

The upfront price gap is real but often overstated. A Clearly Filtered pitcher runs $90–$120. A Big Berkey with two Black filter elements costs $280–$320, and adding PF-2 fluoride filters pushes that closer to $370–$380. So Berkey costs roughly 3x more to start. But the long-term math shifts when you calculate filter replacement costs over several years — Berkey’s 3,000-gallon element lifespan versus Clearly Filtered’s 100-gallon lifespan means Berkey replacement costs are dramatically lower per gallon filtered.

Here’s a rough breakdown of what each approach costs per gallon of filtered water, assuming average use:

1. Clearly Filtered pitcher (year 1): ~$120 upfront + ~$200 in replacement filters = roughly $0.13 per gallon if you filter 2,500 gallons annually
2. Berkey Big Berkey (year 1): ~$320 upfront, filter elements last up to 3,000 gallons each — roughly $0.05–$0.07 per gallon over the element’s lifespan
3. Clearly Filtered (years 2–5): ongoing ~$200/year in replacement filters adds up to $800+ in media costs alone over four years
4. Berkey (years 2–5): filter elements may not need replacement for 2–3 years at average household use, keeping ongoing costs well under $100/year
5. Bottled water comparison: both options cost a fraction of bottled water at roughly $1.50 per gallon retail — the filter investment pays for itself within weeks for most families

One thing worth knowing: some states and utilities offer rebates on point-of-use water filtration purchases, particularly in areas with documented PFAS or lead contamination. It’s worth checking whether your purchase might qualify — the details on what’s available are covered in our guide to Tax Credits and Rebates for Water Filtration Systems, which breaks down what programs exist at the state and utility level.

Which Filter Should You Actually Buy Based on Your Water Situation?

The honest answer is that neither filter is universally better — they’re optimized for different use cases. Here’s how to think through which one fits your situation:

• You’re on municipal tap water and worried about lead, PFAS, or chloramines: Clearly Filtered’s NSF-verified testing protocols make it the more defensible choice, particularly for households with older plumbing where lead above 0.015 mg/L is a realistic concern.
• You’re on well water or want emergency preparedness capability: Berkey’s claimed pathogen and biological reduction performance makes it the stronger option here — no pitcher-style filter should be your primary defense against coliform bacteria in well water.
• You need fluoride reduction: Neither filter handles fluoride well in its base configuration. Berkey requires the PF-2 add-on; Clearly Filtered has introduced limited fluoride-reduction claims but it’s not the pitcher’s primary strength.
• Long-term cost is a priority: Berkey wins on cost-per-gallon over any multi-year horizon, assuming you can absorb the higher upfront price.
• You want the most thoroughly independently verified claims: Clearly Filtered’s NSF/ANSI certification track is more transparent than Berkey’s current documentation — and for many homeowners dealing with regulated contaminants like arsenic or lead, that paper trail matters.

“The single most common mistake I see homeowners make is buying a filter based on a contaminant list instead of a water test. Reduction percentages only matter if those contaminants are actually present at levels of concern in your water. Get the test first, then match the filter to the results — that’s the only comparison that’s actually meaningful for your household.”

Dr. Marcus Elroy, Environmental Engineer and Drinking Water Quality Consultant, formerly with the EPA’s Office of Ground Water and Drinking Water

There’s also a lifestyle dimension that most comparison articles gloss over. Berkey requires counter space — a Royal Berkey is about 19 inches tall and 9.5 inches in diameter. If you live in an apartment with limited countertop real estate, that’s a genuine constraint. Clearly Filtered’s pitcher fits in a standard refrigerator door shelf. Neither system requires installation, which matters if you’re renting, but counter space and storage logistics are real factors that affect whether you’ll actually use the filter consistently.

Some homeowners facing severe contamination problems — high TDS above 500 ppm, multiple heavy metals, or nitrates from agricultural runoff — will find that a pitcher or gravity filter of either brand isn’t the right primary solution at all. Systems like reverse osmosis under-sink units address a wider contamination profile for households with seriously compromised source water. If that’s your situation, it may also be worth looking at the full range of filtration investments, including what a whole-home approach costs — our breakdown of the True Cost of a Whole-House Water Softener, Installed gives useful context for thinking about where a point-of-use filter fits versus a whole-home approach.

The counterintuitive truth about this comparison is that Berkey’s lack of NSF certification isn’t necessarily proof that it underperforms — it’s proof that the company hasn’t submitted to the third-party audit process, which is a different thing. Independent labs have tested Berkey filters and found strong results. But NSF certification exists precisely because “independent lab tests commissioned by the manufacturer” is a weaker standard than “ongoing audits by a body with no financial interest in the outcome.” For families filtering water for infants, immunocompromised members, or in areas with documented regulatory violations, that distinction between tested and certified matters in a concrete way.

Start with a water test, identify your top two or three contaminants of concern, and then use the verified reduction data — not the contaminant count — to make your choice. The filter that reduces the three things actually in your water by 99% is worth far more than the one that claims to reduce 365 things by an unspecified amount. That’s a principle that holds whether you’re comparing these two systems or any others on the market.

Frequently Asked Questions