Clearly Filtered vs ZeroWater: Objective, Data-Driven Comparison

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Clearly Filtered and ZeroWater both make big claims when it comes to reducing contaminants in drinking water. 

We wanted to know how the filters compared performance-wise, including which filter did the better job at reducing contaminants, which had the best design quality, which was the easiest to install and maintain, and so on. So we tested the Clearly Filtered Pitcher and the ZeroWater Ready-Pour Pitcher ourselves, and we’ve shared our data here.

While ZeroWater is more affordable and has more pitcher design and capacity options, Clearly Filtered is better in terms of contaminants reduced and pitcher quality. In our testing, both pitchers performed very similarly, reducing the majority of contaminants in our water, but both also reduced healthy minerals.

📊 Our Testing Data

We tested and analyzed the Clearly Filtered and ZeroWater pitchers across 6 key testing categories. The higher the score, the better the filter performed in a particular category. We’ve shared our scores for both systems below.

FactorClearly FilteredZeroWater
Contaminant Reduction8.248.34
Filtration Rate10.0010.00

We calculated the scores in the table above by testing the filters across a number of performance sub-categories, listed below. If you’re looking for the hard data numbers, this table is for you. 

FactorClearly FilteredZeroWaterWinner
Overall Score8.788.62Clearly Filtered
Health Related Contaminants8.308.30Tie
Aesthetic Related Contaminants9.909.90Tie
Performance CertificationNSF/ANSI 42 & 53NSF/ANSI 42 & 53ZeroWater
Filtration Rate2.27 GPH2.62 GPHZeroWater
Component QualityOutstandingFairClearly Filtered
Component CertificationNSF/ANSI 42, 53 & 372NSF/ANSI 42, 53Clearly Filtered
Servicing RequirementsOutstandingOutstandingTie
Costs$0.55/ gal$0.70/ galClearly Filtered
Warranty Length2 years90 days (vessels), 30 days (filters)Clearly Filtered
ShippingFree shipping to all states$60 order thresholdClearly Filtered
Returns30 daysNoneClearly Filtered

🚰 Contaminant Reduction

To assess the Clearly Filtered and ZeroWater’s contaminant reduction performance, we tested our water before and after filtering it through each pitcher. 

We also made a note of whether or not the pitchers had been certified to reduce any contaminants, and how their certifications compared to their performance claims. 

Our Lab Test Results

We used SimpleLab’s Tap Score city water test to test our water supply and see which contaminants the Clearly Filtered and ZeroWater pitchers reduced. 

Tap Score gave us access to our water quality test reports, which showed us which contaminants were detected in our unfiltered water, and how these concentrations had changed in our filtered water. 

The table below lists the contaminants detected in all three water samples (1x unfiltered and 2x filtered), so you can compare Clearly Filtered and ZeroWater’s performance. 

ContaminantMeasurementUnfiltered WaterClearly Filtered% ChangeZeroWater% Change
Total THMsPPB0NDND3.4n/a
Nitrate (as N)PPM3.53.1-11.43%0-100.00%

ZeroWater just scraped the higher score, but it was incredibly close and came down to a minor difference in the filters’ certification scores. 

Health-Related Contaminants

Our unfiltered water test detected 8 contaminants with possible health effects. Of these, fluoride and uranium were the two contaminants that we were keenest to remove because they were detected in concentrations higher than the Tap Score HGL.

We assessed our test results to see which water filter pitcher did a better job at reducing health-related contaminants. 


The Clearly Filtered pitcher performed exceptionally well at reducing 100% fluoride and uranium, as well as 100% copper and 86% barium. It also did a decent job at reducing 67% strontium and 53% molybdenum, but it only reduced 11% nitrate and 3% sulfate. 

The ZeroWater pitcher performed better overall, reducing 100% fluoride, uranium, barium, strontium, molybdenum, nitrate, and sulfate. It also reduced 97% copper. 

However, we noticed an anomaly with our filtered water test results for both filters. 

After testing the Clearly Filtered pitcher, cobalt had increased to 0.0054 PPM in our water (from 0 PPM initially). Clearly Filtered’s third-party test data says the filter can reduce >98.31% of this heavy metal. We’re planning on doing another test to see if this was a one-time anomaly or an issue with the filter itself. 

Our ZeroWater test detected the presence of 3.4 PPB of chloroform (a disinfection byproduct), in our filtered water, which wasn’t detected in our unfiltered water. 

We think chloroform dissipated from our water when we were filling the other pitchers we tested at the same time with the water from the bucket. This process took a while and we needed to wait until there was less water in the bucket to get the pre-filtration sample. Chloroform’s detection in our filtered water told us that the ZeroWater pitcher hadn’t effectively targeted this contaminant.

Aesthetic Contaminants

We used a treated groundwater supply as our test water, which had been disinfected with chlorine. 

Clearly Filtered Pitcher chlorine test

Our chlorine test strip detected around 1 PPM of chlorine in our unfiltered water, and the Clearly Filtered and ZeroWater pitchers both eliminated this contaminant – a result we’d expected given that they both use activated carbon media in their filters. 

Our water aesthetics were improved post-filtration, and we could no longer detect any chemical tastes or odors in either filtered water sample. 

Minerals, TDS, & pH 

Mineral reduction is typically only an outcome with reverse osmosis systems, which purify water and reduce virtually all dissolved solids, including healthy minerals. This can also alter pH. 

However, a few water filter pitchers we’ve tested have actually reduced beneficial minerals in our water, including the Clearly Filtered and ZeroWater pitchers. 

The Clearly Filtered pitcher reduced calcium by 32% and magnesium by 64% in our testing, as well as sodium by 48%. But our water’s pH actually increased from 7.4 to 8.

Mineral reduction was an unexpected outcome with Clearly Filtered since the manufacturer makes a point of saying that the pitcher filter doesn’t reduce healthy minerals. 

On the other end, ZeroWater is marketed to reduce all total dissolved solids, including minerals, down to 0. 

So we were unsurprised to see that the pitcher had reduced 100% of magnesium and sodium, and calcium by 99%. It also reduced TDS down to 8 PPM, and our water’s pH dipped to 7.0. 

While we don’t like the fact that these pitchers reduced healthy minerals, we prefer the Clearly Filtered here since it didn’t fully remove minerals like ZeroWater did. 

Performance Certifications

Clearly Filtered and ZeroWater have both gone some way to support their contaminant reduction claims with official performance certifications. But ZeroWater has been certified to reduce more contaminants, so it did better than Clearly Filtered here. 

The Clearly Filtered pitcher is certified by the WQA to NSF/ANSI Standard 42, for chlorine reduction, and Standard 53, for the reduction of PFOS and PFOA. Given that Clearly Filtered claims the pitcher can reduce 365 contaminants, we’re not super impressed that it’s only officially certified to reduce 3 of these. 

The ZeroWater pitcher has an NSF certification to Standard 42, for reducing chlorine taste and odors, and Standard 53, for mercury, lead, PFOA, PFOS, and hexavalent chromium removal. So it’s certified to reduce double the number of contaminants than Clearly Filtered, but still, it’s only a fraction of the 43 contaminants that are listed on ZeroWater’s performance datasheet.

While we were pleased to see certifications of some form for the pitchers, we think both manufacturers should get their products certified to reduce as many contaminants as possible. 

🚦Filtration Rate

Both ZeroWater and Clearly Filtered impressed us with their filtration rates. They’re gravity filters, so we measured their rate of filtration in gallons per hour (GPH). 

See the timings and filtration rates for the two pitchers in the next table.

ProductFiltration Rate ScoreFiltration Rate
Clearly Filtered10.002.27 GPH
ZeroWater10.002.62 GPH

The Clearly Filtered pitcher was slightly slower, filtering 0.5 gallons of water in 13 minutes and 12 seconds. This gave it a filtration rate of 2.27 GPH.

The ZeroWater pitcher filtered 0.391 gallons of water in 8 minutes and 56 seconds, and we measured its filtration rate at 2.62 GPH.

There isn’t a big enough difference between the two for us to notice that the ZeroWater filter pitcher was filtering our water at a faster rate. 

Good to Know: We tested both filters when they were still quite new, and it’s a common issue with water filter pitchers that their filtration rate can slow, sometimes quite substantially, towards the end of their lifespan. 

💲 Upfront Cost

In our upfront cost comparison, ZeroWater was the most affordable offering. 

The Clearly Filtered pitcher is one of the most expensive pitcher filters we’ve tested. Most pitchers cost $25-$50 on average, including the price of the first filter. But the Clearly Filtered pitcher was priced at $90 when we got it, or $81 if we signed up to the replacement filter subscription program, Autoship. 

The ZeroWater 12-Cup Ready-Pour Pitcher cost $39.99 when we got it to test, making it around half the price of the Clearly Filtered pitcher. 

If your budget is tight and you’re looking for a water filter pitcher that costs less than $50, ZeroWater is your answer. But make sure to read our later section on ongoing costs, because the ZeroWater pitcher isn’t the most affordable long-term solution. 

ProductPriceFilters Included
Clearly Filtered pitcher$90.001
ZeroWater 12-Cup Ready-Pour Pitcher$39.991

📐 Design

The ZeroWater and Clearly Filtered pitchers look almost identical at a glance. They both use clear plastics in their designs, and both have an upper reservoir that holds unfiltered water, separated from the pitcher by a filter. 

We awarded the pitchers’ design scores as follows: 

ProductDesign ScoreComponent QualityMaterials Safety
Clearly Filtered9.70OutstandingCertified

We gave Clearly Filtered the better score in this category because we were more impressed with the look and feel of its components. 

Filter Models

There’s only one water filter pitcher available on the Clearly Filtered website: the 10-cup Filtered Water Pitcher. It’s sold in just one color combination: white and clear. 

Clearly Filtered Water Filter Pitcher

ZeroWater’s offerings are more extensive. There are a number of pitcher models and sizes to choose from:

ZeroWater’s pitchers are also sold in just one color combination: blue, white, and clear. They all have plastic designs apart from the Glass Ready Pour Dispenser.

zerowater pitcher and dispensers on countertop table

If you want to have the choice of different pitcher sizes, or you’re considering upgrading to a larger dispenser, ZeroWater is your best choice. But we think the Clearly Filtered 10-Cup Pitcher is the best size for most people anyway – it has a decent water-holding capacity without being too heavy when full. 

Component Quality 

We preferred Clearly Filtered’s design quality to ZeroWater’s. 

The Clearly Filtered pitcher has a Tritan plastic design, which is BPA- and BPS-free and has been cleared for use in food contact applications by the FDA. We thought the pitcher felt sturdier and better-made than the ZeroWater pitcher. 

The ZeroWater pitcher is made of BPA-free polypropylene and ABS (a terpolymer). We noted that it felt like most other pitchers we’ve reviewed – thinner and cheaper than Clearly Filtered’s plastic. 

Although the risk of microplastics leaching is supposedly low unless the plastics are exposed to high heat and UV light, the use of plastic for water storage will still be a setback for some people. 

Ultimately, you have to decide whether the benefits of a pitcher with a BPA-free plastic design – affordability, portability, practicality – outweigh the possible setbacks. If you want to reduce your water’s contact with plastic while still benefiting from thorough filtration, consider ZeroWater’s glass filter dispenser

Filter Materials

Both ZeroWater and Clearly Filtered use advanced water filter materials, which explains why they reduce more contaminants than the average carbon-based pitcher filter. 

The Clearly Filtered pitcher filter uses the manufacturer’s affinity filtration technology, which combines carbon block media with a woven stainless steel mesh screen, a composite shell, and several unnamed proprietary materials (we think possibly an ion exchange resin and KDF media). The filter’s unique design sends water through a torturous path, helping to trap as many contaminants as possible.

Clearly Filtered Affinity Filtration filter

ZeroWater’s 5-Stage Filter is also made from activated carbon media, which is combined with cation and anion exchange resins, and three layers of physical filtration.

The filter media in both systems is housed inside a plastic casing. 

Brian holding the ZeroWater 12 cup filter cartridge

Materials Safety Certification

Clearly Filtered and ZeroWater have been certified for materials safety as components of their performance certifications, so they both got the top score here.

The Clearly Filtered pitcher has an additional WQA certification to NSF 372, for lead-free design, which we were pleased to see. 

⚙️ Setup

We know that water filter pitchers appeal to folks who want to avoid a difficult install because they can be assembled in a matter of minutes. 

The Clearly Filtered and ZeroWater pitchers were both quick and easy to set up, but one of them was slightly quicker than the other. 

Here’s how we scored the filters in this category. 

ProductSetup ScoreSetup Time
Clearly Filtered9.50Less than 10 minutes
ZeroWater9.50Less than 10 minutes

ZeroWater and Clearly Filtered both have the same general setup process, which involves: 

  1. Removing the pitcher and reservoirs from their boxes and washing them with warm water with soap. 
  2. Preparing or priming the filter cartridge. 
  3. Slotting the filter into the upper reservoir. 

The Clearly Filtered pitcher is one of the few water filter pitchers we’ve tested that requires the filter to be primed before it can be used. The good news is that this process was super easy, and the instructions were straightforward. We used the included priming bag, and the process didn’t take any longer than 10 minutes.  

On the other end, the ZeroWater filter had an easier setup process than most other pitchers we’ve used. The filter didn’t need to be primed, and we didn’t even have to hold it under running water or soak it for a few minutes. We could just insert it into the reservoir and start using it straight away.

🔧 Maintenance

Here’s how the Clearly Filtered and ZeroWater pitchers compared in the maintenance category, based on their servicing costs and requirements. 

ProductMaintenance ScoreServicing RequirementsCosts
Clearly Filtered8.75Outstanding$0.55/ gal
ZeroWater8.25Outstanding$0.70/ gal

Clearly Filtered did slightly better here because its estimated ongoing cost is lower than ZeroWater’s. 

Servicing Requirements 

To maintain the ZeroWater and Clearly Filtered systems, we essentially just had to repeat our setup tasks. 

This involved replacing the filters, following the same priming instructions in the Clearly Filtered’s case. 

We also washed out the pitchers to keep them clean, as we would with a non-filtering water pitcher. 

Both pitchers were really easy to maintain because they have very few components to keep clean, they’re easy to take apart, and they only have one filter to replace. 

However, both – especially ZeroWater – have short filter lifespans, so although maintenance was easy, we were having to replace our filters more often than we’d like. 

The ZeroWater pitcher comes with a TDS meter, which we could use to monitor the filter performance. This helped us to know when to replace the filter (ZeroWater says you should do so when the TDS reading is 006). Our Clearly Filtered pitcher didn’t come with a means of monitoring the filter lifespan, so we made our own phone calendar reminders for buying replacement filters and monitored the filter for a noticeable decrease in filtration rate.

Maintenance Costs

The Clearly Filtered pitcher doesn’t only have a higher upfront cost – replacement filters are also quite expensive too. We calculated the pitcher’s ongoing cost as $0.55, which is around double the cost of the more affordable pitchers (Brita, PUR, Waterdrop, etc.) that we tested. 

But ZeroWater had an even higher ongoing cost of $0.70/ gallon. The projected filter lifespan varies depending on water quality – we calculated the cost based on the “typical” range on this chart. 

What makes ZeroWater more expensive to maintain is its short filter lifespan. Clearly Filtered can filter up to 100 gallons of water, while ZeroWater filters have a shorter 40-gallon capacity. The filters need replacing more frequently, so the ongoing spend is higher. 

In terms of value for money, we think Clearly Filtered is better here, although neither is the cheapest filter to maintain in the long run. 

🏢 Company

Here, we’ve compared Clearly Filtered and ZeroWater as companies, so you can see how their warranties, shipping, and returns policies differ. 

ProductCompany ScoreWarranty LengthShippingReturns
Clearly Filtered9.002 yearsFree shipping, all orders to all states30 days
ZeroWater7.5090 days for vessels, 30 days for filtersFree shipping on orders above $60 to continental USNone

Clearly Filtered did better across the board in this category, so it got the highest score from us. 

Warranty Length 

Clearly Filtered warrants its pitchers for 24 months from the day of purchase – the best warranty we’ve seen for a water filter pitcher brand. 

ZeroWater didn’t impress us here: its pitcher warranty is 90 days, and its filter cartridge warranty is 30 days. Your ZeroWater filter might not even last 30 days, depending on your water quality, but you can’t make a warranty claim unless the filter is damaged or defective. 


Clearly Filtered also does better here, with its free shipping offering to all customers anywhere in the US. 

ZeroWater also offers free shipping to customers in continental U.S, but only if they’ve spent at least $60. Orders of less than this amount incur a shipping fee.  


Clearly Filtered has a 30-day satisfaction guarantee for its customers, but ZeroWater doesn’t offer a returns policy. 

⛔️ System Setbacks & Flaws

As with all the water filter pitchers we tested, Clearly Filtered and ZeroWater had a few flaws that we want to address here. 

Clearly Filtered Setbacks

  • Only certified to reduce 3 contaminants – We think it’s a shame that the Clearly Filtered pitcher only has certifications to reduce 3 contaminants, given that it’s third-party tested to reduce more than 365.
  • Cobalt concentrations increased – We didn’t like the fact that our filtered water contained cobalt, which hadn’t been detected pre-filtration.
  • Filter needed priming – We spent an extra 10 minutes priming the filter, which we didn’t have to do with ZeroWater. 
  • Expensive – The Clearly Filtered pitcher costs more than ZeroWater upfront. 

ZeroWater Setbacks

  • Tested to reduce fewer contaminants – The ZeroWater pitcher is tested to reduce less than one-sixth of the contaminants that Clearly Filtered. 
  • Only certified to reduce 6 contaminants – ZeroWater’s certifications are better than Clearly Filtered’s, but we still think the pitcher could get certified to reduce many more contaminants. 
  • Poorer design quality – We were less impressed with the ZeroWater pitcher’s design, noting that the plastic felt thinner and flimsier than Clearly Filtered’s. 
  • Costly to maintain – The ZeroWater pitcher has the highest ongoing cost of any water filter pitcher we’ve tested so far.  

🆚 Clearly Filtered or ZeroWater: Which Should You Choose?

Clearly Filtered and ZeroWater both did a better job than most other pitchers at reducing the contaminants detected in our water supply. But which is the best pitcher for your specific situation?

Below, we’ve outlined when you may want to choose one brand over the other.

We Recommend Clearly Filtered If:

You prefer a water filter that has been tested to reduce hundreds of contaminants.
Your priority is to target specific harmful contaminants rather than reducing TDS.
You want a pitcher with a high-quality design that’s backed by one of the longest warranties you’ll find for filters of this kind.

You’ll Prefer ZeroWater If:

You like the reassurance of reducing TDS and being able to use the included TDS meter to check on the filter’s performance.
You prefer to spend less than $50 on a water filter pitcher upfront.
You appreciate having multiple pitcher designs and water-holding capacities to choose from.
  • Laura Shallcross
    Senior Editor

    Laura is a passionate residential water treatment journalist who holds an undergraduate degree in Print Journalism and a master’s degree in Creative Writing. Over a span of 5 years she's written on a range of topics including water softening, well water treatment, and purification processes.

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